Communication control device, communication control method, and wireless communication device

ABSTRACT

There is provided a communication control device including an acquiring section that acquires first position related information relating to positions of one or more wireless communication devices among a plurality of access points that perform transmission of signals to a target device in parallel using an identical frequency resource and second position related information relating to a position of the target device, an estimating section that estimates a distance between the target device and each of the one or more wireless communication devices during the transmission on the basis of the first position related information and the second position related information, and a deciding section that decides transmission timing of each of the plurality of access points for the transmission on the basis of information that includes information on the estimated distance and relates to a distance between the target device and each of the plurality of access points.

TECHNICAL FIELD

The present disclosure relates to a communication control device, acommunication control method, and a wireless communication device.

BACKGROUND ART

Long Term Evolution (LTE)-Advanced of the 3rd Generation PartnershipProject (3GPP) proposes coordinated multipoint (CoMP) transmission andreception in which coordinated eNodeBs transmit and receive signals toand from a single UE.

For example, the CoMP transmission in the downlink increases thereception power level of a UE positioned at the cell edge, which canincrease throughput as a result. The CoMP transmission includes twotechniques such as joint processing (JP) and coordinated schedulingand/or beamforming (CS/CB). In particular, the joint processing includesa technique called joint transmission. According to the jointtransmission, two eNodeBs transmit signals to a single UE in parallelusing the same frequency resource. As a result, the reception powerlevel of the UE can be increased. A variety of techniques relating tothe joint transmission have been proposed.

For example, Patent Literature 1 discloses a technique of adjustingtransmission timing for the joint transmission common to a plurality ofterminals, focusing on a difference in the reception power of signalsfrom two base stations. In addition, for example, Patent Literature 2discloses a technique of deciding transmission timing for the jointtransmission performed by a first base station and a second base stationon the basis of a propagation delay time between each of the first basestation and the second base station and a terminal.

CITATION LIST Patent Literature

Patent Literature 1: JP 2012-175276A

Patent Literature 2: JP 2009-225137A

SUMMARY OF INVENTION Technical Problem

The techniques disclosed in the Patent Literature 1 and PatentLiterature 2, however, presuppose that base stations, which do not movewith the lapse of time, perform joint transmission. However, it ispossible that a first device which may move with the lapse of time, forexample, operates as an access point, and performs joint transmission toa terminal along with a second device. The distance between the firstdevice and the terminal changes with the lapse of time in this case. Thechange in the distance may then change a time from the transmission of asignal by the first device to the reception of the signal by theterminal. Accordingly, the technique disclosed in Patent Literature 2(and the technique disclosed in Patent Literature 1) causes the terminalto have a gap between the reception timing of a signal transmitted bythe first device and the reception timing of a signal transmitted by thesecond device. As a result, an insufficient increase in the receptionpower level of the terminal is a concern.

Accordingly, it is desirable to provide a mechanism that allows thereception power level of signals to be increased even when one or moreof a plurality of access points may move, the access points performingtransmission of the signals to a target device in parallel using thesame frequency resource.

Solution to Problem

According to the present disclosure, there is provided a communicationcontrol device including: an acquiring section configured to acquirefirst position related information and second position relatedinformation, the first position related information relating topositions of one or more wireless communication devices among aplurality of access points that perform transmission of signals to atarget device in parallel using an identical frequency resource, thesecond position related information relating to a position of the targetdevice; an estimating section configured to estimate a distance betweenthe target device and each of the one or more wireless communicationdevices during the transmission on the basis of the first positionrelated information and the second position related information; and adeciding section configured to decide transmission timing of each of theplurality of access points for the transmission on the basis ofinformation that includes information on the estimated distance andrelates to a distance between the target device and each of theplurality of access points. The first position related informationincludes information relating to a change in the position of each of theone or more wireless communication devices.

In addition, according to the present disclosure, there is provided acommunication control method including: acquiring first position relatedinformation and second position related information, the first positionrelated information relating to positions of one or more wirelesscommunication devices among a plurality of access points that performtransmission of signals to a target device in parallel using anidentical frequency resource, the second position related informationrelating to a position of the target device; estimating a distancebetween the target device and each of the one or more wirelesscommunication devices during the transmission on the basis of the firstposition related information and the second position relatedinformation; and deciding transmission timing of each of the pluralityof access points for the transmission on the basis of information thatincludes information on the estimated distance and relates to a distancebetween the target device and each of the plurality of access points.The first position related information includes information relating toa change in the position of each of the one or more wirelesscommunication devices.

Furthermore, according to the present disclosure, there is provided awireless communication device including: a communication control sectionconfigured to operate the wireless communication device as an accesspoint; and an acquiring section configured to, when the wirelesscommunication device and one or more access points perform transmissionof signals to a target device in parallel using an identical frequencyresource, acquire information on transmission timing of the wirelesscommunication device for the transmission after a communication controldevice decides transmission timing of the wireless communication deviceand each of the one or more access points for the transmission. Thecommunication control section controls transmission of the wirelesscommunication device for the transmission on the basis of thetransmission timing of the wireless communication device for thetransmission. The transmission timing of the wireless communicationdevice and each of the one or more access points for the transmission isdecided on the basis of information relating to a distance between thetarget device and the wireless communication device and between thetarget device and each of the one or more access points. The informationrelating to the distance includes information on a distance to beestimated between the target device and the wireless communicationdevice during the transmission. The distance to be estimated isestimated on the basis of individual position related informationrelating to a position of the wireless communication device and positionrelated information relating to a position of the target device. Theindividual position related information includes information on a changein the position of the wireless communication device.

Advantageous Effects of Invention

According to the present disclosure as described above, it becomespossible to increase the reception power level of signals even when oneor more of a plurality of access points may move, the access pointsperforming transmission of the signals to a target device in parallelusing the same frequency resource.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system according to a first embodiment.

FIG. 2 is a block diagram illustrating an example of a configuration ofa control server according to the first embodiment.

FIG. 3 is an explanatory diagram for describing an example of anestimated position of a dynamic AP.

FIG. 4 is an explanatory diagram for describing an example oftransmission timing of a dynamic AP.

FIG. 5 is a block diagram illustrating an example of a configuration ofa dynamic AP according to the first embodiment.

FIG. 6A is a flowchart illustrating an example of a schematic flow ofcommunication control processing according to the first embodiment for adownlink.

FIG. 6B is a flowchart illustrating the example of the schematic flow ofthe communication control processing according to the first embodimentfor a downlink.

FIG. 6C is a flowchart illustrating the example of the schematic flow ofthe communication control processing according to the first embodimentfor a downlink.

FIG. 7A is a flowchart illustrating an example of a schematic flow ofcommunication control processing according to the first embodiment for adownlink.

FIG. 7B is a flowchart illustrating the example of the schematic flow ofthe communication control processing according to the first embodimentfor a downlink.

FIG. 7C is a flowchart illustrating the example of the schematic flow ofthe communication control processing according to the first embodimentfor a downlink.

FIG. 8 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system according to a first modifiedexample of the first embodiment.

FIG. 9 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system according to a second modifiedexample of the first embodiment.

FIG. 10 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system according to a secondembodiment.

FIG. 11 is a block diagram illustrating an example of a configuration ofa control server according to the second embodiment.

FIG. 12 is a block diagram illustrating an example of a configuration ofa small cell base station according to the second embodiment.

FIG. 13A is a flowchart illustrating an example of a schematic flow ofcommunication control processing according to the second embodiment.

FIG. 13B is a flowchart illustrating the example of the schematic flowof the communication control processing according to the secondembodiment.

FIG. 13C is a flowchart illustrating the example of the schematic flowof the communication control processing according to the secondembodiment.

FIG. 14 is an explanatory diagram illustrating a first example of aschematic configuration of a communication system according to amodified example of the second embodiment.

FIG. 15 is an explanatory diagram illustrating a second example of theschematic configuration of the communication system according to themodified example of the second embodiment.

FIG. 16 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system according to a third embodiment.

FIG. 17 is a block diagram illustrating an example of a configuration ofa control server according to the third embodiment.

FIG. 18 is a block diagram illustrating an example of a configuration ofa relay station according to the third embodiment.

FIG. 19A is a flowchart illustrating an example of a schematic flow ofcommunication control processing according to the third embodiment for adownlink.

FIG. 19B is a flowchart illustrating the example of the schematic flowof the communication control processing according to the thirdembodiment for a downlink.

FIG. 19C is a flowchart illustrating the example of the schematic flowof the communication control processing according to the thirdembodiment for a downlink.

FIG. 20A is a flowchart illustrating an example of a schematic flow ofcommunication control processing according to the third embodiment for adownlink.

FIG. 20B is a flowchart illustrating the example of the schematic flowof the communication control processing according to the thirdembodiment for a downlink.

FIG. 20C is a flowchart illustrating the example of the schematic flowof the communication control processing according to the thirdembodiment for a downlink.

FIG. 21 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system according to a first modifiedexample of the third embodiment.

FIG. 22 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system according to a second modifiedexample of the third embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, preferred embodiments of the present disclosure will bedescribed in detail with reference to the appended drawings. Note that,in the present description and the drawings, elements that havesubstantially the same function and structure are denoted with the samereference signs, and repeated explanation is omitted.

The description will be now made in the following order.

1. First Embodiment

1.1. Schematic Configuration of Communication System

1.2. Configuration of Each Device

-   -   1.2.1. Configuration of Control Server    -   1.2.2. Configuration of Dynamic Access Point

1.3. Flow of Processing

1.4. Modified Examples

2. Second Embodiment

2.1. Schematic Configuration of Communication System

2.2. Configuration of Each Device

-   -   2.2.1. Configuration of Control Server    -   2.2.2. Configuration of Small Cell Base Station

2.3. Flow of Processing

2.4. Modified Examples

3. Third Embodiment

3.1. Schematic Configuration of Communication System

3.2. Configuration of Each Device

-   -   3.2.1. Configuration of Control Server    -   3.2.2. Configuration of Relay Station

3.3. Flow of Processing

3.4. Modified Examples

<<<1. First Embodiment>>>

First of all, a first embodiment of the present disclosure will bedescribed with reference to FIGS. 1 to 9. A plurality of wirelesscommunication devices (such as terminal devices) that operate as accesspoints perform transmission of signals to a target device (such as abase station or a terminal device) in parallel using the same frequencyresource in the first embodiment.

<<1.1. Schematic Configuration of Communication System>>

First of all, a schematic configuration of a communication system 1-1according to the first embodiment of the present disclosure will bedescribed with reference to FIG. 1. FIG. 1 is an explanatory diagramillustrating an example of a schematic configuration of thecommunication system 1-1 according to the first embodiment. FIG. 1illustrates that the communication system 1-1 includes a base station10, a terminal device 20, a control server 100-1, and a dynamic accesspoint 200 (which will be referred to as “dynamic AP 200” below).

(Base Station 10)

The base station 10 wirelessly communicates with a device positionedwithin a cell 11. For example, the base station 10 wirelesslycommunicates with the terminal device 20 positioned within the cell 11.That is to say, the base station 10 transmits a signal to the terminaldevice 20, and receives a signal transmitted by the terminal device 20.In addition, the base station 10 wirelessly communicates with thedynamic AP 200 positioned within the cell 11. That is to say, the basestation 10 transmits a signal to the dynamic AP 200, and receives asignal transmitted by the dynamic AP 200.

(Terminal Device 20)

When positioned within the cell 11, the terminal device 20 wirelesslycommunicates with the base station 10. That is to say, the terminaldevice 20 transmits a signal to the base station 10, and receives asignal transmitted by the base station 10.

The terminal device 20 is, for example, a movable device. That is tosay, the terminal device 20 may move with the lapse of time. As anexample, the terminal device 20 is a smartphone carried by a user.

(Dynamic AP 200)

The dynamic AP 200 is a wireless communication device, and wirelesslycommunicates with the base station 10 when the dynamic AP 200 ispositioned within the cell 11. That is to say, the dynamic AP 200transmits a signal to the base station 10, and receives a signaltransmitted by the base station 10.

The dynamic AP 200 is, for example, a movable device. That is to say,the dynamic AP 200 may move with the lapse of time. As an example, thedynamic AP 200 is a smartphone carried by a user.

In addition, the dynamic AP 200 can operate as an access point. Forexample, the dynamic AP 200 wirelessly communicates with the terminaldevice 20, and relays communication between the base station 10 and theterminal device 20. More specifically, the dynamic AP 200, for example,receives a signal transmitted by the base station 10, and transmits asignal of data addressed to the terminal device 20 to the terminaldevice 20, the signal being included in the received signal. Forexample, the dynamic AP 200 receives a signal transmitted by theterminal device 20, and transmits a signal of data included in thereceived signal to the base station 10.

The plurality of dynamic APs 200 perform transmission of signals to atarget device in parallel using the same frequency resource especiallyin the first embodiment. For example, the target device is the basestation 10 or a terminal device 20. In other words, the plurality ofdynamic APs 200 perform joint transmission to the base station 10 or theterminal device 20.

(Control Server 100-1)

When a plurality of access points perform transmission of signals to atarget device in parallel using the same frequency resource, the controlserver 100-1 decides transmission timing for the transmission.

As discussed above, a plurality of dynamic APs perform transmission ofsignals to a target device in parallel using the same frequency resourcein the first embodiment. The control server 100-1 decides transmissiontiming of each of the plurality of dynamic APs for the transmission inthis case. Each of the plurality of dynamic APs then performs thetransmission on the basis of the decided transmission timing.

(Others)

Additionally, the base station 10 and the control server 100-1communicate with each other, for example, via a wired backbone line.

Meanwhile, the base station 10 and the dynamic AP 200 communicate witheach other, for example, via a wireless backbone line. Morespecifically, a time slot for communication via a wireless backbone lineis, for example, prepared in the cell 11. That is to say, a frequencyband used for wireless communication between the base station 10 and thedynamic AP 200 is the same as a frequency band used for wirelesscommunication between the terminal device 20, and the base station 10and the dynamic AP, but these kinds of wireless communication areperformed at different time.

<<1.2. Configuration of Each Device>>

Next, the configurations of the control server 100-1 and the dynamic AP200 will be described.

<1.2.1. Configuration of Control Server>

An example of the configuration of the control server 100-1 according tothe first embodiment will be described with reference to FIGS. 2 to 4.FIG. 2 is a block diagram illustrating an example of the configurationof the control server 100-1 according to the first embodiment. FIG. 2illustrates that the control server 100-1 includes a networkcommunication unit 110, a storage unit 120, and a control unit 130.

(Network Communication Unit 110)

The network communication unit 110 communicates with another device. Forexample, the network communication unit 110 communicates with the basestation 10. More specifically, for example, the network communicationunit 110 communicates with the base station 10 via a wired backboneline.

The network communication unit 110 includes, for example, a LANterminal, a transmission circuit, and another communication processingcircuit.

(Storage Unit 120)

The storage unit 120 stores a program and data for operating the controlserver 100-1. The storage unit 120 includes, for example, a magneticstorage device such as a hard disk, or nonvolatile memory such aselectrically erasable and programmable read only memory (EEPROM) andflash memory.

(Control Unit 130)

The control unit 130 provides a variety of functions of the controlserver 100-1. The control unit 130 includes, for example, a processorsuch as a central processing unit (CPU) or a digital signal processor(DSP). The control unit 130 then provides the variety of functions byexecuting a program stored in the storage unit 120 or another storagemedium.

The storage unit 130 includes an information acquiring section 131, ajoint transmission determining section 133, a scheduling section 135, adistance estimating section 137, and a transmission timing decidingsection 139.

(Information Acquiring Section 131)

The information acquiring section 131 acquires first position relatedinformation (which will be referred to as DAP position relatedinformation below) and second position related information (which willbe referred to as target device position related information below), theDAP position related information relating to the positions of the one ormore dynamic APs 200 among a plurality of access points that performtransmission of signals to a target device in parallel using the samefrequency resource, the target device position related informationrelating to the position of the target device.

For example, the information acquiring section 131 acquires individualposition related information from each of the one or more dynamic APs200 via the network communication unit 110, thereby acquiring the DAPposition related information.

For example, the target device is the base station 10 or the terminaldevice 20. When the target device is the terminal device 20, theinformation acquiring section 131 acquires target device positionrelated information from the terminal device 20 via the networkcommunication unit 110. Meanwhile, when the target device is the basestation 10, the information acquiring section 131, for example, acquirestarget device position related information (i.e. information relating tothe position of the base station 10) stored in the storage unit 120.

DAP Position Related Information

For example, the DAP position related information includes informationrelating to a change in the position of each of the one or more dynamicAPs 200. More specifically, the information relating to a change in theposition is, for example, positional information and movementinformation on each of the one or more dynamic APs 200.

For example, the positional information indicates the position of thedynamic AP 200 at some time point. As an example, the position P_(T) ofthe dynamic AP 200 at some time point T is represented by planecoordinates (X, Y). That is to say, the positional information indicatesthe position P_(T)=(X, Y).

Meanwhile, the movement information indicates, for example, the movingvelocity V_(T) of the dynamic AP 200 at some time point T. The movingvelocity includes moving speed and a moving direction. As an example,the moving velocity V_(T) of the dynamic AP 200 at some time point T isrepresented by a plane vector (V_(X), V_(Y)). That is to say, themovement information indicates the moving velocity V_(T)=(V_(X), V_(Y)).

Additionally, the plurality of access points are, for example, the oneor more dynamic APs 200 especially in the first embodiment. That is tosay, each of the plurality of access points is the dynamic AP 200, andthe plurality of dynamic APs 200 perform transmission of signals to atarget device in parallel using the same frequency resource.Accordingly, the DAP position related information includes information(such as positional information and movement information) relating to achange in the position of each of the plurality of dynamic APs 200.

Target Device Position Related Information

For example, the target device is the base station 10 or the terminaldevice 20. The target device position related information becomesdifferent in accordance with whether the target device is the basestation 10 or the terminal device 20.

Target Device is Terminal Device

For example, the target device is the terminal device 20. That is tosay, transmission of signals to the terminal device 20 in parallel isperformed using the same frequency resource. The target device positionrelated information is position related information relating to theposition of the terminal device 20 in this case.

Furthermore, the target device position related information includes,for example, information relating to a change in the position of theterminal device 20 in this case. More specifically, the informationrelating to a change in the position is, for example, positionalinformation and movement information on the terminal device 20. Thepositional information and the movement information have been describedin connection with the DAP position related information.

Target Device is Base Station

For example, the target device is the base station 10. That is to say,transmission of signals to the base station 10 in parallel is performedusing the same frequency resource. That is to say, the target deviceposition related information is position related information relating tothe position of the base station 10.

Furthermore, the target device position related information includes,for example, positional information indicating the position of the basestation 10 in this case. For example, the positional informationindicates a fixed position that does not change with the lapse of time.In addition, the positional information is stored, for example, in thestorage unit 120 in advance.

(Joint Transmission Determining Section 133)

The joint transmission determining section 133 determines whether or nota plurality of access points perform transmission of signals to a targetdevice in parallel using the same frequency resource.

For example, once the terminal device 20 requests communication in thecell 11 via a plurality of access points, the joint transmissiondetermining section 133 determines whether or not the plurality ofaccess points perform transmission of signals to a target device inparallel using the same frequency resource.

For example, the joint transmission determining section 133 determineswhether or not the plurality of dynamic APs 200 perform transmission ofsignals to the terminal device 20 in parallel using the same frequencyresource. In other words, the joint transmission determining section 133determines whether or not joint transmission to the terminal device 20in the downlink is performed.

More specifically, the joint transmission determining section 133, forexample, estimates the reception power of signals in the terminal device20, and compares the estimated reception power with a threshold, thesignals being transmitted by the base station 10. If the estimatedreception power falls below the threshold, the joint transmissiondetermining section 133 determines that the plurality of dynamic APs 200perform transmission of signals to the terminal device 20 in parallelusing the same frequency resource. That is to say, it is determined thatthe base station 10 transmits signals including the same data to theplurality of dynamic APs 200, and the plurality of dynamic APs 200transmit the signals including the same data to the terminal device 20in parallel using the same frequency resource.

For example, the joint transmission determining section 133 determineswhether or not the plurality of dynamic APs 200 perform transmission ofsignals to the base station 10 in parallel using the same frequencyresource. In other words, the joint transmission determining section 133determines whether or not joint transmission to the base station 10 inthe uplink is performed.

More specifically, the joint transmission determining section 133, forexample, estimates the reception power of signals in the base station10, and compares the estimated reception power with a threshold, thesignals being transmitted by the terminal device 20. If the estimatedreception power falls below the threshold, the joint transmissiondetermining section 133 determines that the plurality of dynamic APs 200perform transmission of signals to the base station 10 in parallel usingthe same frequency resource. That is to say, it is determined that theterminal device 20 transmits signals including the same data to the twoor more dynamic APs 200, and the two or more dynamic APs 200 transmitthe signals including the same data to the base station 10 in parallelusing the same frequency resource.

(Scheduling Section 135)

The scheduling section 135 allocates a radio resource for performingtransmission of signals to a target device in parallel using the samefrequency resource. In other words, the scheduling section 135 allocatesa radio resource for performing joint transmission to a target device.

For example, when the communication system 1-1 is compliant with LTE,the radio resource is one or more resource blocks as an example. That isto say, the scheduling section 135 allocates one or more resource blocksfor performing joint transmission to each of a plurality of accesspoints.

Additionally, the plurality of access points are, for example, the oneor more dynamic APs 200 in the first embodiment. That is to say, each ofthe plurality of access points is the dynamic APs 200. Accordingly, thescheduling section 135 allocates the one or more resource blocks to eachof the plurality of dynamic APs 200.

In addition, the scheduling section 135, for example, generatesallocation information relating to the allocation of a radio resourcefor performing the transmission (i.e. transmission of signals to atarget device in parallel using the same frequency resource). Forexample, the allocation information includes information on atransmission frame with which the transmission of signals to the targetdevice is performed. For example, the transmission frame is a sub-frame.The information on a transmission frame includes identificationinformation (such as a system frame number (SFN)) on a radio frame andidentification information (such as a sub-frame number) on a sub-frameincluded in the radio frame in this case. The allocation informationincludes identification information on a frequency resource with whichthe transmission is performed. The allocation information includes sucha kind of information, thereby identifying one or more resource blockswith which the transmission is performed.

The scheduling section 135 then provides the allocation information tothe base station 10 via the network communication unit 110. As a result,the allocation information is transmitted to the plurality of dynamicAPs 200 by the base station 10. As a result, the radio resource is usedin the cell 11 by each of the plurality of access points (i.e. dynamicAPs 200) for joint transmission.

In addition, the scheduling section 135 provides the allocationinformation to the distance estimating section 137.

(Distance Estimating Section 137)

The distance estimating section 137 estimates the distance between thetarget device and each of the one or more dynamic APs 200 during thetransmission of signals to the target device on the basis of the DAPposition related information and the target device position relatedinformation.

For example, the distance estimating section 137 estimates the distancefurther on the basis of the allocation information. More specifically,the distance estimating section 137, for example, estimates the distancefurther on the basis of the information on a transmission frame includedin the allocation information.

As specific processing, the distance estimating section 137 estimatesthe position of each of the one or more dynamic APs during thetransmission of signals to the target device, for example, on the basisof the DAP position related information and the allocation information.A specific example will be described below in terms of this point withreference to FIG. 3.

FIG. 3 is an explanatory diagram for describing an example of theestimated position of the dynamic AP 200. FIG. 3 illustrates that theposition P_(T) of the dynamic AP 200 at some time point T and the movingvelocity V_(T) of the dynamic AP 200 at some time point T are acquiredfrom the DAP position related information. In addition, a difference ΔTbetween the time point T and a starting time point of a transmissionframe with which the transmission of signals to the target device isperformed is calculated from the time point T and transmission timingincluded in the allocation information. The position P_(T+ΔT) of thedynamic AP 200 during the transmission (i.e. joint transmission) ofsignals to the target device is then estimated, for example, as below.P _(T+ΔT) ≈P _(T) +V _(T) ·ΔT=(X+V _(X) ·ΔT,Y+V _(Y) ·ΔT)  [Math 1]

For example, when the target device is the terminal device 20, thedistance estimating section 137 estimates the position of the terminaldevice 20 during the transmission of signals to the target device on thebasis of the target device position related information and theallocation information in the same way for the estimation of theposition of the dynamic AP 200. Meanwhile, for example, when the targetdevice is the base station 10, the distance estimating section 137acquires positional information indicating the position of the basestation 10 from the target device position related information.

The distance estimating section 137 then estimates the distance betweenthe target device and each of the one or more dynamic APs during thetransmission of signals to the target device on the basis of theestimated position of each of the one or more dynamic APs and theposition of the target device (terminal device 20 or base station 10).

For example, in this way, the distance estimating section 137 estimatesthe distance between the target device and each dynamic AP 200.

As discussed above, each of the plurality of access points is, forexample, the dynamic AP 200 in the first embodiment. The distanceestimating section 137 thus estimates the distance between the targetdevice and each of the plurality of dynamic APs 200 during thetransmission of signals to the target device.

(Transmission Timing Deciding Section 139)

The transmission timing deciding section 139 decides transmission timingof each of the plurality of access points for the transmission ofsignals to the target device on the basis of information relating to thedistance between the target device and each of the plurality of accesspoints. The information relating to the distance includes information onthe estimated distance between the target device and each of the one ormore dynamic APs 200.

For example, the decided transmission timing is the timing of thetransmission in a transmission frame in which the transmission ofsignals to the target device is performed.

As discussed above, each of the plurality of access points is, forexample, the dynamic APs 200 in the first embodiment. Accordingly, forexample, the transmission timing deciding section 139 decidestransmission timing of each of the plurality of dynamic APs 200 for thetransmission of signals to the target device on the basis of informationon the estimated distance between the target device and each of theplurality of dynamic APs 200.

As specific processing, the transmission timing deciding section 139,for example, selects the farthest dynamic AP 200 from the target devicefrom the information on the estimated distance between the target deviceand each of the plurality of dynamic APs 200. The transmission timingdeciding section 139 then decides, as transmission timing of theselected dynamic AP 200, a starting time point of a transmission framewith which the transmission (i.e. joint transmission) of signals to thetarget device is performed, for example.

The transmission timing deciding section 139, for example, estimates apropagation delay time (which will be referred to as “referencepropagation delay time” below) from the selected dynamic AP 200 to thetarget device on the basis of information on the distance between thetarget device and the selected dynamic AP 200. In addition, thetransmission timing deciding section 139 estimates a propagation delaytime of signals for each of the other dynamic APs 200 from the dynamicAP 200 to the target device on the basis of information on the distancebetween the target device and the dynamic AP 200. The transmissiontiming deciding section 139 then calculates a difference between theestimated propagation delay time and the reference propagation delaytime. The transmission timing deciding section 139 decides, astransmission timing of the dynamic AP 200, a time point that is delayedfrom the starting time point of a transmission frame as much as thedifference.

For example, in this way, the transmission timing deciding section 139decides transmission timing of each of the plurality of dynamic APs forthe transmission (i.e. joint transmission) of signals to the targetdevice. A specific example of the decision of transmission timing willbe described below with reference to FIG. 4.

FIG. 4 is an explanatory diagram for describing an example oftransmission timing of the dynamic AP 200. FIG. 4 illustratestransmission timing at which a dynamic AP 200A and a dynamic AP 200Bperform transmission (i.e. joint transmission) of signals to a targetdevice in parallel using the same frequency resource. For example, thedynamic AP 200A is farther from the target device than the dynamic AP200B. Accordingly, a starting time point of a transmission frame withwhich joint transmission is performed is decided as transmission timingT_(A) of the dynamic AP 200A for the joint transmission. A time ΔD is adifference between an estimated propagation delay time D_(A) of signalsfrom the dynamic AP 200A to a target device and an estimated propagationdelay time D_(B) of signals from the dynamic AP 200B to the targetdevice. Accordingly, a time point delayed, as much as the time ΔD, fromthe starting time point (i.e. transmission timing T_(A)) of atransmission frames with which joint transmission is performed isdecided as transmission timing T_(B) of the dynamic AP 200B for thejoint transmission.

In addition, the transmission timing deciding section 139, for example,provides information on the decided transmission timing to a pluralityof access points via the network communication unit 110, the pluralityof access points performing the transmission (i.e. joint transmission)of signals to the target device. The information on the decidedtransmission timing is provided to the plurality of dynamic APs 200 inthe first embodiment. For example, the information is provided via thebase station 10.

Additionally, the transmission timing deciding section 139 may decidethe transmission timing further on the basis of propagation pathinformation relating to a propagation path between the target device andeach of the one or more dynamic APs 200. The propagation pathinformation may include information relating to a change in the phase ofthe propagation path. As an example, the propagation path informationmay include information on the frequency of a radio resource used forjoint transmission. The frequency may change the extent to which thephase of signals is shifted in the propagation path in the jointtransmission. Accordingly, the further use of such a kind of propagationpath information allows more appropriate transmission timing to bedecided. That is to say, it becomes possible to cancel phase shift ofthe propagation path.

<1.2.2. Configuration of Dynamic Access Point>

An example of the configuration of the dynamic AP 200 according to thefirst embodiment will be described with reference to FIG. 5. FIG. 5 is ablock diagram illustrating an example of the configuration of thedynamic AP 200 according to the first embodiment. FIG. 5 illustratesthat the dynamic AP 200 includes a wireless communication unit 210, asensing unit 220, a storage unit 230, and a control unit 240.

(Wireless Communication Unit 210)

The wireless communication unit 210 wirelessly communicates with anotherdevice. That is to say, the wireless communication unit 210 transmits asignal to the other device, and receives a signal transmitted by theother device.

For example, the wireless communication unit 210 wirelessly communicateswith the base station 10. In addition, when the dynamic AP 200 operatesas an access point, the wireless communication unit 210 wirelesslycommunicates with the terminal device 20.

The wireless communication unit 210 includes, for example, acommunication antenna, an RF circuit, and another communicationprocessing circuit.

(Sensing Unit 220)

The sensing unit 220 detects information relating to the dynamic AP 200.The sensing unit 220 then provides the detected information to thecontrol unit 240.

For example, the sensing unit 220 detects positional informationindicating the position of the dynamic AP 200. Specifically, the sensingunit 220 includes, for example, a GPS sensor, and detects informationindicating the position P_(T) of the dynamic AP 200 which is representedby plane coordinates (X, Y).

In addition, the sensing unit 220 detects, for example, directioninformation indicating the direction of the dynamic AP 200.Specifically, the sensing unit 220 includes, for example, a geomagneticsensor, and detects information indicating the magnetic field strengthin the triaxial directions of the dynamic AP 200 which are orthogonal toeach other.

In addition, the sensing unit 220 detects, for example, accelerationinformation indicating the acceleration of the dynamic AP 200.Specifically, the sensing unit 220 includes, for example, anacceleration sensor, and detects information indicating the accelerationin the triaxial directions of the dynamic AP 200 which are orthogonal toeach other.

(Storage Unit 230)

The storage unit 230 stores a program and data for operating the dynamicAP 200. The storage unit 230 includes, for example, a magnetic storagedevice such as a hard disk, or nonvolatile memory such as EEPROM andflash memory.

(Control Unit 240)

The control unit 240 provides a variety of functions of the dynamic AP200. The control unit 240 includes, for example, a processor such as aCPU or a DSP. The control unit 240 then provides the variety offunctions by executing a program stored in the storage unit 230 oranother storage medium.

The control unit 240 includes an information acquiring section 241, aninformation providing section 243, a transmission timing acquiringsection 245, and a communication control section 247.

(Information Acquiring Section 241)

The information acquiring section 241 acquires individual positionrelated information relating to the position of the dynamic AP 200. Thatis to say, the information acquiring section 241 acquires individualposition related information relating to the position of the dynamic AP200 among DAP position related information acquired by the controlserver 100-1.

For example, the individual position related information includesinformation relating to a change in the position of the dynamic AP 200.More specifically, the information relating to a change in the positionis, for example, positional information and movement information on thedynamic AP 200.

For example, the information acquiring section 241 acquires positionalinformation on the position of the dynamic AP 200 from the sensing unit220.

In addition, the information acquiring section 241, for example,acquires direction information and acceleration information on thedynamic AP 200 from the sensing unit 220, and calculates the movingvelocity V_(T) (moving speed and moving direction) of the dynamic AP 200on the basis of the direction information and the accelerationinformation. For example, in this way, the information acquiring section241 acquires movement information indicating the moving velocity of thedynamic AP 200.

As described above, the information acquiring section 241 acquiresinformation (positional information and movement information) relatingto a change in the position of the dynamic AP 200, thereby acquiringindividual position related information.

(Information Providing Section 243)

The information providing section 243 provides individual positionrelated information relating to the position of the dynamic AP 200 tothe control server 100-1. For example, the information providing section243 provides the individual position related information to the controlserver 100-1 via the wireless communication unit 210 upon receiving theindividual position related information from the information acquiringsection 241.

(Transmission Timing Acquiring Section 245)

When the dynamic AP 200 and one or more access points performtransmission of signals to a target device in parallel using the samefrequency resource, the control server 100-1 decides transmission timingof the dynamic AP 200 and each of the one or more access points for thetransmission. The transmission timing acquiring section 245 thenacquires information on the transmission timing of the dynamic AP 200for the transmission.

For example, once the control server 100-1 provides the information onthe transmission timing to the dynamic AP 200 via the base station 10,the transmission timing acquiring section 245 acquires the informationon the transmission timing via the wireless communication unit 210.

In addition, the transmission timing acquiring section 245 also acquiresallocation information including information on a transmission framewith which the transmission of signals to the target device isperformed.

For example, once the control server 100-1 provides the allocationinformation to the base station 10, the base station 10 transmits theallocation information to the dynamic AP 200. The transmission timingacquiring section 245 then acquires the allocation information via thewireless communication unit 210.

(Communication Control Section 247)

The communication control section 247 controls communication performedby the dynamic AP 200.

The communication control section 247 operates the dynamic AP 200 as anaccess point in particular.

For example, the communication control section 247 wirelesslycommunicates with the terminal device 20 via the wireless communicationunit 210, and relays communication between the base station 10 and theterminal device 20. More specifically, the communication control section247, for example, causes the wireless communication unit 210 to receivesignals transmitted by the base station 10, and to transmit signals ofdata addressed to the terminal device 20 to the terminal device 20, thesignals being included in the received signals. For example, thecommunication control section 247 causes the wireless communication unit210 to receive signals transmitted by the terminal device 20, and totransmit signals of data included in the received signals to the basestation 10.

In particular, based on the transmission timing of the dynamic AP 200for the transmission (i.e. joint transmission) of signals to a targetdevice in parallel using the same frequency resource, the communicationcontrol section 247 controls the transmission of the dynamic AP 200 forthe transmission.

For example, once the transmission timing acquiring section 245 acquirestransmission timing and allocation information, the communicationcontrol section 247 causes the wireless communication unit 210 totransmit signals to a target device at the transmission timing in atransmission frame in which the transmission of signals to the targetdevice is performed. Additionally, the target device is the terminaldevice 20 in the downlink, and the base station 10 in the uplink.

<<1.3. Flow of Processing>>

Next, an example of communication control processing according to thefirst embodiment will be described with reference to FIGS. 6A to 7C.

(Communication Control Processing for Downlink)

First of all, an example of communication control processing for thedownlink will be described with reference to FIGS. 6A to 6C. Each ofFIGS. 6A to 6C is a flowchart illustrating an example of a schematicflow of communication control processing according to the firstembodiment for the downlink.

First of all, the information acquiring section 241 of the dynamic AP200A acquires individual position related information relating to theposition of the dynamic AP 200A (step S501). In addition, theinformation acquiring section 241 of the dynamic AP 200B also acquiresindividual position related information relating to the position of thedynamic AP 200B (step S503). Furthermore, the terminal device 20 alsoacquires position related information relating to the position of theterminal device 20 (step S505).

The terminal device 20 then transmits a request for communication by theterminal device 20 in the cell 11 and the position related information(i.e. target device position related information) relating to theposition of the terminal device 20 to the dynamic AP 200B and thedynamic AP 200A (steps S507 and S509).

The information providing section 243 of the dynamic AP 200B transmitsthe request for communication by the terminal device 20 in the cell 11,the position related information relating to the position of theterminal device 20, and the individual position related informationrelating to the position of the dynamic AP 200B to the base station 10via the wireless communication unit 210 (S511).

The information providing section 243 of the dynamic AP 200A alsotransmits the request for communication by the terminal device 20 in thecell 11, the position related information relating to the position ofthe terminal device 20, and the individual position related informationrelating to the position of the dynamic AP 200A to the base station 10via the wireless communication unit 210 (S513).

Thereafter, the base station 10 transmits the request for communicationby the terminal device 20 in the cell 11 and the received positionrelated information to the control server 100-1 (S515). The receivedposition related information includes the position related informationrelating to the position of the terminal device 20, the individualposition related information relating to the position of the dynamic AP200A, and the individual position related information relating to theposition of the dynamic AP 200B.

The joint transmission determining section 133 of the control server100-1 then determines whether or not the dynamic AP 200A and the dynamicAP 200B perform transmission of signals to the terminal device 20 inparallel using the same frequency resource (S517). Here, for example,the joint transmission determining section 133 determines that thetransmission of signals to the terminal device 20 is performed.

The scheduling section 135 of the control server 100-1 then allocates aradio resource for performing the transmission of signals to theterminal device 20 (S519).

Moreover, the distance estimating section 137 of the control server100-1 estimates the distance between the terminal device 20 and each ofthe dynamic AP 200A and the dynamic AP 200B during the transmission ofsignals to the terminal device 20 on the basis of the position relatedinformation on each device (S521).

The transmission timing deciding section 139 of the control server 100-1then decides transmission timing of each of the dynamic AP 200A and thedynamic AP 200B for the transmission (i.e. joint transmission) ofsignals to the terminal device 20 on the basis of information on theestimated distance (S523).

Thereafter, the control server 100-1 transmits downlink data addressedto the terminal device 20, allocation information relating to theallocation of a radio resource, and information on the decidedtransmission timing to the base station 10 (S525).

Moreover, the base station 10 transmits the downlink data addressed tothe terminal device 20, the allocation information, and the informationon the decided transmission timing to the dynamic AP 200A and thedynamic AP 200B (S527 and S529).

Thereafter, the dynamic AP 200A and the dynamic AP 200B wait for atarget frame corresponding to the allocated radio resource (S531 andS533).

The communication control section 247 of the dynamic AP 200A thentransmits signals including the downlink data to the terminal device 20with the target frame at the decided transmission timing of the dynamicAP 200A (S535).

The communication control section 247 of the dynamic AP 200B alsotransmits signals including the downlink data to the terminal device 20with the target frame at the decided transmission timing of the dynamicAP 200B (S537).

(Communication Control Processing for Uplink)

Furthermore, an example of communication control processing for theuplink will be described with reference to FIGS. 7A to 7C. Each of FIGS.7A to 7C is a flowchart illustrating an example of a schematic flow ofcommunication control processing according to the first embodiment forthe downlink.

First of all, the information acquiring section 241 of the dynamic AP200A acquires individual position related information relating to theposition of the dynamic AP 200A (step S601). In addition, theinformation acquiring section 241 of the dynamic AP 200B also acquiresindividual position related information relating to the position of thedynamic AP 200B (step S603).

The terminal device 20 then transmits a request for communication by theterminal device 20 in the cell 11 to the dynamic AP 200B and the dynamicAP 200A (steps S605 and S607).

The information providing section 243 of the dynamic AP 200B transmitsthe request for communication by the terminal device 20 in the cell 11and the individual position related information relating to the positionof the dynamic AP 200B to the base station 10 via the wirelesscommunication unit 210 (S609).

The information providing section 243 of the dynamic AP 200A alsotransmits the request for communication by the terminal device 20 in thecell 11 and the individual position related information relating to theposition of the dynamic AP 200A to the base station 10 via the wirelesscommunication unit 210 (S611).

Thereafter, the base station 10 transmits the request for communicationby the terminal device 20 in the cell 11, the individual positionrelated information relating to the position of the dynamic AP 200A, andthe individual position related information relating to the position ofthe dynamic AP 200B to the control server 100-1 (S613).

The joint transmission determining section 133 of the control server100-1 then determines whether or not the dynamic AP 200A and the dynamicAP 200B perform transmission of signals to the base station 10 inparallel using the same frequency resource (S615). Here, for example,the joint transmission determining section 133 determines that thetransmission of signals to the base station 10 is performed.

The scheduling section 135 of the control server 100-1 then allocates aradio resource for performing the transmission of signals to the basestation 10 (S617).

Moreover, the distance estimating section 137 of the control server100-1 estimates the distance between the base station 10 and each of thedynamic AP 200A and the dynamic AP 200B during the transmission ofsignals to the base station 10 on the basis of the position relatedinformation on each device (S619).

The transmission timing deciding section 139 of the control server 100-1then decides transmission timing of each of the dynamic AP 200A and thedynamic AP 200B for the transmission (i.e. joint transmission) ofsignals to the base station 10 on the basis of information on theestimated distance (S621).

Thereafter, the control server 100-1 transmits allocation informationrelating to the allocation of a radio resource and information on thedecided transmission timing to the base station 10 (S623).

Moreover, the base station 10 transmits the allocation information andthe information on the decided transmission timing to the dynamic AP200A and the dynamic AP 200B (S625 and S627).

Thereafter, the terminal device 20 transmits signals including uplinkdata to the dynamic AP 200A and the dynamic AP 200B (S629 and S631).

The dynamic AP 200A and the dynamic AP 200B then wait for a target framecorresponding to the allocated radio resource (S633 and S635).

Thereafter, the communication control section 247 of the dynamic AP 200Athen transmits signals including the uplink data to the base station 10with the target frame at the decided transmission timing of the dynamicAP 200A (S637).

The communication control section 247 of the dynamic AP 200B alsotransmits signals including the uplink data to the base station 10 withthe target frame at the decided transmission timing of the dynamic AP200B (S639).

<<1.4. Modified Examples>>

Next, modified examples of the first embodiment will be described withreference to FIGS. 8 and 9.

FIG. 1 has illustrated an example in which the plurality of dynamic APs200 communicate with the base station 10 of the cell 11, and performjoint transmission to the base station 10 or the terminal device 20 asan example of the first embodiment.

(First Modified Example)

Meanwhile, the plurality of dynamic APs 200 may also communicate with asmall cell base station 30 of a small cell 31 a part or the whole ofwhich overlaps with the cell 11, and perform joint transmission to thesmall cell base station 30 or the terminal device 20 as a first modifiedexample of the first embodiment. That is to say, a target device that isa target of joint transmission may be a small cell base station. Aspecific example of the first modified example will be described withreference to FIG. 8.

FIG. 8 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system 1-1A according to the firstmodified example of the first embodiment. As illustrated in FIG. 8, thecommunication system 1-1A may include the small cell base station 30 inthe first modified example of the first embodiment. When the dynamic AP200A and the dynamic AP 200B communicate with the small cell basestation 30, transmission of signals to the small cell base station 30 orthe terminal device 20 in parallel may be performed using the samefrequency resource. As with the base station 10, transmission timing forthe joint transmission to the terminal device 20 or the small cell basestation 30 is decided even in such a case of the small cell base station30.

It goes without saying that when communicating with the base station 10(i.e. macrocell base station), the plurality of dynamic APs 200 mayperform transmission of signals to the base station 10 or the terminaldevice 20 in parallel using the same frequency resource in the firstmodified example.

(Second Modified Example)

Joint transmission to the terminal device 20 may be performed as asecond modified example of the first embodiment when a part of theplurality of dynamic APs 200 communicates with the small cell basestation 30 of the small cell 31, and the rest of the plurality ofdynamic APs 200 communicates with the base station 10. A specificexample of the second modified example will be described with referenceto FIG. 8.

FIG. 9 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system 1-1B according to the secondmodified example of the first embodiment. As illustrated in FIG. 9, thecommunication system 1-1B may also include the small cell base station30 in the second modified example of the first embodiment. When thedynamic AP 200A communicates with the base station 10 and the dynamic AP200B communicates with the small cell base station 30, the dynamic AP200A and the dynamic AP 200B may perform transmission of signals to theterminal device 20 in parallel using the same frequency resource.Transmission timing for joint transmission to the terminal device 20 isdecided in the same way even in such a case.

It goes without saying that when communicating with the base station 10(i.e. macrocell base station), the plurality of dynamic APs 200 mayperform transmission of signals to the base station 10 or the terminaldevice 20 in parallel using the same frequency resource in the secondmodified example. When the plurality of dynamic APs 200 communicate withthe small cell base station 30, transmission of signals to the terminaldevice 20 or the small cell base station 30 in parallel may be performedusing the same frequency resource.

<<<2. Second Embodiment>>>

Next, a second embodiment of the present disclosure will be describedwith reference to FIGS. 10 to 15. One or more wireless communicationdevices (such as terminal devices) that operate as access points, andone or more base stations perform transmission of signals to a terminaldevice in parallel using the same frequency resource in the secondembodiment.

<<2.1. Schematic Configuration of Communication System>>

First of all, a schematic configuration of a communication system 1-2according to the second embodiment of the present disclosure will bedescribed with reference to FIG. 10. FIG. 10 is an explanatory diagramillustrating an example of a schematic configuration of thecommunication system 1-2 according to the second embodiment. FIG. 10illustrates that the communication system 1-2 includes a macrocell basestation 10, a terminal device 20, a control server 100-2, a dynamic AP200, and a small cell base station 300.

(Macrocell Base Station 10)

The macrocell base station 10 wirelessly communicates with a devicepositioned within a macrocell 11. This point has been described in thefirst embodiment.

(Terminal Device 20)

When positioned within the macrocell 11, the terminal device 20wirelessly communicates with the macrocell base station 10. The terminaldevice 20 is, for example, a movable device. These points have beendescribed in the first embodiment.

When positioned within a small cell 31, the terminal device 20wirelessly communicates with the small cell base station 300 in thesecond embodiment. That is to say, the terminal device 20 transmits asignal to the small cell base station 300, and receives a signaltransmitted by the small cell base station 300.

(Dynamic AP 200)

The dynamic AP 200 is a wireless communication device, and wirelesslycommunicates with the macrocell base station 10 when the dynamic AP 200is positioned within the macrocell 11. The dynamic AP 200 is, forexample, a movable device. In addition, the dynamic AP 200 can operateas an access point. These points have been described in the firstembodiment.

When positioned within the small cell 31, the dynamic AP 200 wirelesslycommunicates with the small cell base station 300. That is to say, thedynamic AP 200 transmits a signal to the small cell base station 300,and receives a signal transmitted by the small cell base station 300.

The one or more dynamic APs 200 perform transmission of signals to theterminal device 20 in parallel along with one or more base stations(such as the one or more small cell base stations 300) by using the samefrequency resource especially in the second embodiment. In other words,the one or more dynamic APs 200 perform joint transmission to theterminal device 20 along with the one or more base stations (such as theone or more small cell base stations 300).

(Small Cell Base Station 300)

The small cell base station 300 wirelessly communicates with a devicepositioned within the small cell 31, a part or the whole of whichoverlaps with the macro cell 11.

For example, the small cell base station 300 wirelessly communicateswith the terminal device 20 positioned within the small cell 31. That isto say, the small cell base station 300 transmits a signal to theterminal device 20, and receives a signal transmitted by the terminaldevice 20.

For example, the small cell base station 300 also wirelesslycommunicates with the dynamic AP 200 positioned within the small cell31. That is to say, the small cell base station 300 transmits a signalto the dynamic AP 200, and receives a signal transmitted by the dynamicAP 200.

The one or more small cell base stations 300, for example, performtransmission of signals to the terminal device in parallel along withthe one or more dynamic APs 200 by using the same frequency resourceespecially in the second embodiment. In other words, the one or moresmall cell base stations 300 perform joint transmission to the terminaldevice 20 along with the one or more dynamic APs 200.

(Control Server 100-2)

When a plurality of access points perform transmission of signals to atarget device in parallel using the same frequency resource, the controlserver 100-2 decides transmission timing for the transmission.

The plurality of access points include the one or more dynamic APs 200.Additionally, the plurality of access points include one or more basestations especially in the second embodiment. That is to say, asdiscussed above, one or more dynamic APs and one or more base stations(such as the small cell base stations 300) perform transmission ofsignals to a target device in parallel using the same frequency resourcein the second embodiment. The control server 100-2 decides transmissiontiming of each of the one or more dynamic APs and the one or more basestations (such as the small cell base stations 300) for the transmissionin this case. Each of the one or more dynamic APs 200 and the one ormore base stations (such as the small cell base stations 300) thenperforms the transmission on the basis of the decided transmissiontiming.

(Others)

Additionally, the macrocell base station 10 and the control server 100-2communicate with each other, for example, via a wired backbone line.Meanwhile, the macrocell base station 10 and the dynamic AP 200communicate with each other, for example, via a wireless backbone line.These points have been described in the first embodiment.

In addition, the small cell base station 300 and the control server100-2 communicate with each other, for example, via a wired backboneline in the second embodiment. Meanwhile, the small cell base station300 and the dynamic AP 200 communicate with each other, for example, viaa wireless backbone line.

<<2.2. Configuration of Each Device>>

Next, the configurations of the control server 100-2 and the small cellbase station 300 will be described. Additionally, the configuration ofthe dynamic AP 200 has been described in the first embodiment.

<2.2.1. Configuration of Control Server>

An example of the configuration of the control server 100-2 according tothe second embodiment will be described with reference to FIG. 11. FIG.11 is a block diagram illustrating an example of the configuration ofthe control server 100-2 according to the second embodiment. FIG. 11illustrates that the control server 100-2 includes a networkcommunication unit 110, a storage unit 120, and a control unit 140.

Additionally, there is no difference in particular in the networkcommunication unit 110 and the storage unit 120 between the firstembodiment and the second embodiment. Accordingly, the control unit 140alone will be described here.

(Control Unit 140)

The control unit 140 provides a variety of functions of the controlserver 100-2. The control unit 140 includes, for example, a processorsuch as a CPU or a DSP. The control unit 140 then provides the varietyof functions by executing a program stored in the storage unit 120 oranother storage medium.

The storage unit 140 includes an information acquiring section 141, ajoint transmission determining section 143, a scheduling section 145, adistance estimating section 147, and a transmission timing decidingsection 149.

(Information Acquiring Section 141)

The information acquiring section 141 acquires first position relatedinformation (i.e. DAP position related information) and second positionrelated information (i.e. target device position related information),the DAP position related information relating to the positions of theone or more dynamic APs 200 among a plurality of access points thatperform transmission of signals to a target device in parallel using thesame frequency resource, the target device position related informationrelating to the position of the target device.

For example, the information acquiring section 141 acquires individualposition related information from each of the one or more dynamic APs200 via the network communication unit 110, thereby acquiring the DAPposition related information.

In addition, the target device is the terminal device 20 in the secondembodiment. The information acquiring section 141 acquires target deviceposition related information from the terminal device 20 via the networkcommunication unit 110.

The plurality of access points include one or more base stationsespecially in the second embodiment. The information acquiring section141 further acquires third position related information (“base stationposition related information” below) relating to the positions of theone or more base stations.

For example, the one or more base stations include at least the onesmall cell base station 300. More specifically, each of the one or morebase stations is, for example, the small cell base station 300.

For example, the information acquiring section 141 acquires base stationposition related information (such as information relating to thepositions of the one or more small cell base stations 300) stored in thestorage unit 120.

DAP Position Related Information

For example, the DAP position related information includes informationrelating to a change in the position of each of the one or more dynamicAPs 200. This point has been described in the first embodiment.

Additionally, the one or more dynamic APs 200 may be, for example, theone dynamic AP 200 or the plurality of dynamic APs 200 in the secondembodiment.

Target Device Position Related Information

The target device position related information is position relatedinformation relating to the position of the terminal device 20 in thesecond embodiment.

Furthermore, the target device position related information includes,for example, information relating to a change in the position of theterminal device 20. This point has been described in the firstembodiment.

Base Station Position Related Information

The base station position related information includes positionalinformation indicating the positions of the one or more base stations.For example, each of the one or more base stations is the small cellbase station 300, and the base station position related informationincludes positional information indicating the positions of the one ormore small cell base stations 300.

For example, the positional information indicates a fixed position thatdoes not change with the lapse of time. In addition, the positionalinformation is stored, for example, in the storage unit 120 in advance.

(Joint Transmission Determining Section 143)

The joint transmission determining section 143 determines whether or nota plurality of access points perform transmission of signals to a targetdevice in parallel using the same frequency resource.

For example, once the terminal device 20 requests communication in themacrocell 11 via a plurality of access points, the joint transmissiondetermining section 143 determines whether or not the plurality ofaccess points perform transmission of signals to a target device inparallel using the same frequency resource.

The joint transmission determining section 143 determines whether or notthe one or more dynamic APs 200 and one or more base stations (such asthe one or more small cell base stations 300) perform transmission ofsignals to the terminal device 20 in parallel using the same frequencyresource especially in the second embodiment. In other words, the jointtransmission determining section 143 determines whether or not jointtransmission to the terminal device 20 in the downlink is performed.

More specifically, the joint transmission determining section 143, forexample, estimates the reception power of signals in the terminal device20, and compares the estimated reception power with a threshold, thesignals being transmitted by the macrocell base station 10. If theestimated reception power falls below the threshold, the jointtransmission determining section 143 determines that the one or moredynamic APs 200 and the one or more small cell base stations 300 performtransmission of signals to the terminal device 20 in parallel using thesame frequency resource. That is to say, it is determined that themacrocell base station 10 transmits signals including the same data tothe one or more dynamic APs 200 and the one or more small cell basestations 300, and the one or more dynamic APs 200 and the one or moresmall cell base stations 300 transmit the signals including the samedata to the terminal device 20 in parallel using the same frequencyresource.

(Scheduling Section 145)

The scheduling section 145 allocates a radio resource for performingtransmission of signals to the terminal device 20 in parallel using thesame frequency resource. In other words, the scheduling section 145allocates a radio resource for performing joint transmission to theterminal device 20.

For example, when the communication system 1-2 is compliant with LTE,the radio resource is one or more resource blocks as an example. That isto say, the scheduling section 145 allocates one or more resource blocksfor performing joint transmission to each of a plurality of accesspoints.

The plurality of access points include, for example, the one or moredynamic APs 200 and one or more base stations (such as the small cellbase stations 300) especially in the second embodiment. Accordingly, thescheduling section 145 allocates each of the one or more resource blocksto the one or more dynamic APs 200 and the one or more base stations.

In addition, the scheduling section 145, for example, generatesallocation information relating to the allocation of a radio resourcefor performing the transmission (i.e. transmission of signals to atarget device in parallel using the same frequency resource). This pointhas been described in the first embodiment.

The scheduling section 145 then provides, for example, the allocationinformation to the macrocell base station 10 and the one or more smallcell base stations 300 via the network communication unit 110. As aresult, the allocation information is transmitted to the one or moredynamic APs 200, for example, by the macrocell base station 10. Theradio resource is used by each of the one or more dynamic APs 200 andthe one or more small cell base stations 300 for joint transmission inthe macrocell 11.

In addition, the scheduling section 145 provides the allocationinformation to the distance estimating section 147.

Additionally, when the one or more base stations are the one or moresmall cell base stations 300, a radio resource in an almost blanksubframe (ABS) for the small cell 31 is, for example, allocated.

(Distance Estimating Section 147)

The distance estimating section 147 estimates the distance between theterminal device 20 and each of the one or more dynamic APs 200 duringthe transmission of signals to the terminal device 20 on the basis ofthe DAP position related information and the target device positionrelated information. This point has been described in the firstembodiment.

The distance estimating section 147 estimates the distance between theterminal device 20 and each of the one or more base stations during thetransmission of signals to the terminal device 20 on the basis of thebase station position related information and the target device positionrelated information especially in the second embodiment. For example,the one or more base stations are the one or more small cell basestation 300. Additionally, the distance between the terminal device 20and each of the one or more small cell base stations 300 may also beestimated in the same technique for the distance between the terminaldevice 20 and the one or more dynamic APs 200.

(Transmission Timing Deciding Section 149)

The transmission timing deciding section 149 decides transmission timingof each of the plurality of access points for the transmission ofsignals to the terminal device 20 on the basis of information relatingto the distance between the terminal device 20 and each of the pluralityof access points. The information relating to the distance includesinformation on the estimated distance between the terminal device 20 andeach of the one or more dynamic APs 200.

In addition, the information relating to the distance includesinformation on the estimated distance between the terminal device 20 andeach of the one or more base stations in the second embodiment. Forexample, the one or more base stations are the one or more small cellbase station 300.

For example, the decided transmission timing is timing of thetransmission in a transmission frame in which the transmission ofsignals to the terminal device 20 is performed.

As specific processing, the transmission timing deciding section 149,for example, selects the farthest device from the terminal device 20among the one or more dynamic APs 200 and the one or more small cellbase stations 300. The device is selected on the basis of information onthe estimated distance between the terminal device 20 and each of theone or more dynamic APs 200 and information on the estimated distancebetween the terminal device 20 and each of the one or more small cellbase stations 300. The transmission timing deciding section 149 thendecides, as transmission timing of the selected device (dynamic AP 200or small cell base station 300), a starting point of a transmissionframe with which the transmission (i.e. joint transmission) of signalsto the terminal device 20 is performed, for example.

The transmission timing deciding section 149, for example, estimates apropagation delay time (which will be referred to as “referencepropagation delay time” below) from the selected device to the terminaldevice 20 on the basis of the information on the distance between theterminal device 20 and the selected device. In addition, thetransmission timing deciding section 149 estimates a propagation delaytime of signals from the other individual devices of the one or moredynamic APs 200 and the one or more small cell base stations 300 to theterminal device 20 for the other individual devices on the basis ofinformation on the distance between the terminal device 20 and theindividual devices. The transmission timing deciding section 149 thencalculates a difference between the estimated propagation delay time andthe reference propagation delay time. The transmission timing decidingsection 149 decides, as transmission timing of the individual devices(dynamic APs 200 or small cell base stations 300), a time point that isdelayed from the starting time point of a transmission frame as much asthe difference.

In this way, the transmission timing deciding section 149, for example,decides transmission timing of each of the one or more dynamic APs 200and the one or more small cell base stations 300 for the transmission(i.e. joint transmission) of signals to the target device.

In addition, the transmission timing deciding section 149, for example,provides information on the decided transmission timing to a pluralityof access points via the network communication unit 110, the pluralityof access points performing the transmission (i.e. joint transmission)of signals to the target device. The information on the decidedtransmission timing is provided to the one or more dynamic APs 200 andthe one or more small cell base stations 300 in the second embodiment.

Additionally, the transmission timing deciding section 149 may decidethe transmission timing further on the basis of propagation pathinformation relating to a propagation path between the target device andeach of the one or more dynamic APs 200. This point has been describedin the first embodiment.

<2.2.2. Configuration of Small Cell Base Station>

An example of the configuration of the small cell base station 300according to the second embodiment will be described with reference toFIG. 12. FIG. 12 is a block diagram illustrating an example of theconfiguration of the small cell base station 300 according to the secondembodiment. FIG. 12 illustrates that the small cell base station 300includes a wireless communication unit 310, a network communication unit320, a storage unit 330, and a control unit 340.

(Wireless Communication Unit 310)

The wireless communication unit 310 wirelessly communicates with anotherdevice. That is to say, the wireless communication unit 310 transmits asignal to the other device, and receives a signal transmitted by theother device.

For example, the wireless communication unit 310 wirelessly communicateswith the terminal device 20. In addition, the wireless communicationunit 310 wirelessly communicates, for example, with the dynamic AP 200.

The wireless communication unit 310 includes, for example, acommunication antenna, an RF circuit, and another communicationprocessing circuit.

(Network Communication Unit 320)

The network communication unit 320 communicates with another device. Forexample, the network communication unit 320 communicates with thecontrol server 100-2. For example, the network communication unit 320communicates with the macrocell base station 10. More specifically, forexample, the network communication unit 320 communicates with thecontrol server 100-2 and the macrocell base station 10 via a wiredbackbone line.

The network communication unit 110 includes, for example, a LANterminal, a transmission circuit, and another communication processingcircuit.

(Storage Unit 330)

The storage unit 330 stores a program and data for operating the smallcell base station 300. The storage unit 330 includes, for example, amagnetic storage device such as a hard disk, or nonvolatile memory suchas EEPROM and flash memory.

(Control Unit 340)

The control unit 340 provides a variety of functions of the small cellbase station 300. The control unit 340 includes, for example, aprocessor such as a CPU or a DSP. The control unit 340 then provides thevariety of functions by executing a program stored in the storage unit330 or another storage medium.

The control unit 340 includes a transmission timing acquiring section341 and a communication control section 343.

(Transmission Timing Acquiring Section 341)

The transmission timing acquiring section 341 acquires information onthe transmission timing of the small cell base station 300 for thetransmission (i.e. joint transmission) of signals to the terminal device20.

In addition, the transmission timing acquiring section 341 also acquiresallocation information including information on a transmission framewith which the transmission of signals to the terminal device 20 isperformed.

For example, once the control server 100-2 provides the information onthe transmission timing and the allocation information to the small cellbase station 30, the transmission timing acquiring section 341 acquiresthe information on the transmission timing and the allocationinformation via the network communication unit 320.

(Communication Control Section 343)

The communication control section 343 controls communication performedby the small cell base station 300.

In particular, based on the transmission timing of the small cell basestation 300 for the transmission (i.e. joint transmission) of signals tothe terminal device 20 in parallel using the same frequency resource,the communication control section 343 controls the transmission of thesmall cell base station 300 for the transmission.

For example, once the transmission timing acquiring section 341 acquirestransmission timing and allocation information, the communicationcontrol section 343 causes the wireless communication unit 310 totransmit signals to the terminal device 20 at the transmission timing ina transmission frame with which the transmission of signals to theterminal device 20 is performed.

<<2.3. Flow of Processing>>

Next, an example of communication control processing according to thesecond embodiment will be described with reference to FIGS. 13A to 13C.Each of FIGS. 13A to 13C is a flowchart illustrating an example of aschematic flow of communication control processing according to thesecond embodiment.

First of all, the information acquiring section 241 of the dynamic AP200 acquires individual position related information relating to theposition of the dynamic AP 200 (step S701). Furthermore, the terminaldevice 20 also acquires position related information relating to theposition of the terminal device 20 (step S703).

The terminal device 20 then transmits a request for communication by theterminal device 20 in the cell 11 and the position related informationrelating to the position of the terminal device 20 to the small cellbase station 300 and the dynamic AP 200 (steps S705 and S707).

The information providing section 243 of the dynamic AP 200 transmitsthe request for communication by the terminal device 20 in the cell 11,the position related information relating to the position of theterminal device 20, and the individual position related informationrelating to the position of the dynamic AP 200 to the macrocell basestation 10 via the wireless communication unit 210 (S709).

In addition, the small cell base station 300 transmits a request forcommunication by the terminal device 20 in the cell 11 and the positionrelated information relating to the position of the terminal device 20to the control server 100-2 via the network communication unit 320(S711).

Meanwhile, the macrocell base station 10 transmits the informationreceived from the dynamic AP 200 to the control server 100-2 (S713).

The joint transmission determining section 143 of the control server100-2 then determines whether or not the dynamic AP 200 and the smallcell base station 300 perform transmission of signals to the terminaldevice 20 in parallel using the same frequency resource (S715). Here,for example, the joint transmission determining section 143 determinesthat the transmission of signals to the terminal device 20 is performed.

The scheduling section 145 of the control server 100-2 then allocates aradio resource for performing the transmission of signals to theterminal device 20 (S717)

Moreover, the distance estimating section 147 of the control server100-2 estimates the distance between the terminal device 20 and each ofthe dynamic AP 200 and the small cell base station 300 during thetransmission of signals to the terminal device 20 on the basis of theposition related information on each device (S719).

The transmission timing deciding section 149 of the control server 100-2then decides transmission timing of each of the dynamic AP 200 and thesmall cell base station 300 for the transmission (i.e. jointtransmission) of signals to the terminal device 20 on the basis ofinformation on the estimated distance (S721).

Thereafter, the control server 100-2 transmits downlink data addressedto the terminal device 20, allocation information relating to theallocation of a radio resource, and information on the decidedtransmission timing of the dynamic AP 200 to the macrocell base station10 (S723).

In addition, the control server 100-2 transmits the downlink dataaddressed to the terminal device 20, the allocation information relatingto the allocation of a radio resource, and information on the decidedtransmission timing of the small cell base station 300 to the small cellbase station 30 (S725).

Moreover, the macrocell base station 10 transmits the downlink dataaddressed to the terminal device 20, the allocation information, and theinformation on the decided transmission timing of the dynamic AP 200 tothe dynamic AP 200 (S727).

Thereafter, the dynamic AP 200 and the small cell base station 300 waitfor a target frame corresponding to the allocated radio resource (S729and S731).

The communication control section 343 of the small cell base station 300then transmits signals including the downlink data to the terminaldevice 20 with the target frame at the decided transmission timing ofthe small cell base station 300 (S733).

The communication control section 247 of the dynamic AP 200 alsotransmits signals including the downlink data to the terminal device 20with the target frame at the decided transmission timing of the dynamicAP 200 (S735).

<<2.4. Modified Examples>>

Next, a modified example of the second embodiment will be described withreference to FIGS. 14 and 15.

As discussed above, the one or more dynamic APs 200 and one or more basestations perform joint transmission to the terminal device 20 in thesecond embodiment. As an example of the second embodiment, an examplehas been described in which the one or more base stations are the one ormore small cell base stations 300.

Meanwhile, the one or more base stations may include at least the onebase station 10 of a macrocell as a modified example of the secondembodiment. For example, the one or more base stations may be the one ormore base station 10 of a macrocell. That is to say, the one or moredynamic APs 200 and the one or more macrocell base stations 10 mayperform joint transmission to the terminal device 20. The one or moredynamic APs 200 may communicate with the small cell base station 300 orthe macrocell base station 10 in this case. A specific example of themodified example will be described with reference to FIGS. 14 and 15.

FIG. 14 is an explanatory diagram illustrating a first example of aschematic configuration of a communication system 1-2A according to amodified example of the second embodiment. As illustrated in FIG. 14,the dynamic AP 200, which communicates, for example, with the small cellbase station 300, and the macrocell base station 10 may performtransmission of signals to the terminal device 20 in parallel using thesame frequency resource in the modified example of the secondembodiment. Transmission timing for joint transmission to the terminaldevice 20 is decided in the same way even in such a case.

FIG. 15 is an explanatory diagram illustrating a second example of aschematic configuration of a communication system 1-2B according to amodified example of the second embodiment. As illustrated in FIG. 15,the dynamic AP 200, which communicates, for example, with the macrocellbase station 10, and the macrocell base station 10 may performtransmission of signals to the terminal device 20 in parallel using thesame frequency resource in the modified example of the secondembodiment. Transmission timing for joint transmission to the terminaldevice 20 is decided in the same way even in such a case.

Additionally, it goes without saying that the one or more dynamic APs200 and the one or more small cell base stations 300 may perform jointtransmission to the terminal device 20 in the modified example of thesecond embodiment. In addition, the one or more dynamic APs 200, the oneor more small cell base stations 300, and the one or more macrocell basestations 10 may perform joint transmission to the terminal device 20 inthe modified example of the second embodiment.

<<<3. Third Embodiment>>>

Next, a third embodiment of the present disclosure will be describedwith reference to FIGS. 16 to 22. One or more wireless communicationdevices (such as terminal devices) that operate as access points, and arelay station perform transmission of signals to a target device (suchas a base station or a terminal device) in parallel using the samefrequency resource in the third embodiment.

<<3.1. Schematic Configuration of Communication System>>

First of all, a schematic configuration of a communication system 1-3according to the third embodiment of the present disclosure will bedescribed with reference to FIG. 16. FIG. 16 is an explanatory diagramillustrating an example of a schematic configuration of thecommunication system 1-3 according to the third embodiment. FIG. 16illustrates that the communication system 1-3 includes a macrocell basestation 10, a terminal device 20, a control server 100-3, a dynamic AP200, and a relay station 400.

(Macrocell Base Station 10)

The macrocell base station 10 wirelessly communicates with a devicepositioned within a macrocell 11. This point has been described in thefirst embodiment.

(Terminal Device 20)

When positioned within the macrocell 11, the terminal device 20wirelessly communicates with the macrocell base station 10. The terminaldevice 20 is, for example, a movable device. These points have beendescribed in the first embodiment.

For example, the terminal device 20 wirelessly communicates with therelay station 400 as needed, thereby communicating with the base station10 in the third embodiment. That is to say, the terminal device 20transmits a signal to the relay station 400, which provides a relay fromthe terminal device 20 to the base station 10, and receives a signalfrom the relay station 400, which provides a relay from the base station10 to the terminal device 20.

(Dynamic AP 200)

The dynamic AP 200 is a wireless communication device, and wirelesslycommunicates with the macrocell base station 10 when the dynamic AP 200is positioned within the macrocell 11. The dynamic AP 200 is, forexample, a movable device. In addition, the dynamic AP 200 can operateas an access point. These points have been described in the firstembodiment.

For example, the dynamic AP 200 wirelessly communicates with the relaystation 400 as needed, thereby communicating with the base station 10 inthe third embodiment. That is to say, the dynamic AP 200 transmits asignal to the relay station 400, which provides a relay from the dynamicAP 200 to the base station 10, and receives a signal from the relaystation 400, which provides a relay from the base station 10 to thedynamic AP 200.

The one or more dynamic APs 200 perform transmission of signals to atarget device in parallel along with the one or more relay stations 400by using the same frequency resource especially in the third embodiment.For example, the target device is the base station 10 or the terminaldevice 20. In other words, the one or more dynamic APs 200 perform jointtransmission to the base station 10 or the terminal device 20 along withthe one or more relay stations 400.

(Relay Station 400)

The relay station 400 provides a relay between one device and anotherdevice as needed. The relay station 400 provides a relay to the targetdevice especially in the third embodiment. For example, the targetdevice is the base station 10 or the terminal device 20.

For example, the relay station 400 provides a relay to the terminaldevice 20 as needed. For example, the relay station 400 provides a relayfrom the base station 10 to the terminal device 20. That is to say, inthe downlink, the relay station 400 receives signals including dataaddressed to the terminal device 20 from the base station 10, andtransmits the signals including the data to the terminal device 20.

For example, the relay station 400 provides a relay to the base station10 as needed. For example, the relay station 400 provides a relay fromthe terminal device 20 to the base station 10. That is to say, in theuplink, the relay station 400 receives signals including data addressedto another device from the terminal device 20, and transmits the signalsincluding the data to the base station 10. For example, the relaystation 400 provides a relay from the dynamic AP 200 to the base station10. That is to say, in the uplink, the relay station 400 receivessignals including data addressed to another device from the dynamic AP200, and transmits the signals including the data to the base station10.

The one or more relay stations 400 perform transmission of signals to atarget device in parallel along with the one or more dynamic APs 200 byusing the same frequency resource especially in the third embodiment.For example, the target device is the base station 10 or the terminaldevice 20. In other words, the one or more relay stations 400 performjoint transmission to the base station 10 or the terminal device 20along with the one or more dynamic APs 200.

(Control Server 100-3)

When a plurality of access points perform transmission of signals to atarget device in parallel using the same frequency resource, the controlserver 100-3 decides transmission timing for the transmission.

The plurality of access points include the one or more dynamic APs 200.Additionally, the plurality of access points include the one or morerelay stations 400, which provide relays to the target device,especially in the third embodiment. That is to say, as discussed above,the one or more dynamic APs and the one or more relay stations 400perform transmission of signals to a target device in parallel using thesame frequency resource in the third embodiment. The control server100-3 decides transmission timing of each of the one or more dynamic APsand the one or more relay stations 400 for the transmission in thiscase. Each of the one or more dynamic APs 200 and the one or more relaystations 400 then performs the transmission on the basis of the decidedtransmission timing.

(Others)

Additionally, the macrocell base station 10 and the control server 100-3communicate with each other, for example, via a wired backbone line.Meanwhile, the macrocell base station 10 and the dynamic AP 200communicate with each other, for example, via a wireless backbone line.These points have been described in the first embodiment.

In addition, the relay station 400 and the base station 10 communicatewith each other, for example, via a wireless backbone line in the thirdembodiment.

<<3.2. Configuration of Each Device>>

Next, the configurations of the control server 100-3 and the relaystation 400 will be described. Additionally, the configuration of thedynamic AP 200 has been described in the first embodiment.

<3.2.1. Configuration of Control Server>

An example of the configuration of the control server 100-3 according tothe third embodiment will be described with reference to FIG. 17. FIG.17 is a block diagram illustrating an example of the configuration ofthe control server 100-3 according to the third embodiment. FIG. 17illustrates that the control server 100-3 includes a networkcommunication unit 110, a storage unit 120, and a control unit 150.

Additionally, there is no difference in particular in the networkcommunication unit 110 and the storage unit 120 between the firstembodiment and the third embodiment. Accordingly, the control unit 150alone will be described here.

(Control Unit 150)

The control unit 150 provides a variety of functions of the controlserver 100-3. The control unit 150 includes, for example, a processorsuch as a CPU or a DSP. The control unit 150 then provides the varietyof functions by executing a program stored in the storage unit 120 oranother storage medium.

The control unit 150 includes an information acquiring section 151, ajoint transmission determining section 153, a scheduling section 155, adistance estimating section 157, and a transmission timing decidingsection 159.

(Information Acquiring Section 151)

The information acquiring section 151 acquires first position relatedinformation (i.e. DAP position related information) and second positionrelated information (i.e. target device position related information),the DAP position related information relating to the positions of theone or more dynamic APs 200 among a plurality of access points thatperform transmission of signals to a target device in parallel using thesame frequency resource, the target device position related informationrelating to the position of the target device.

For example, the information acquiring section 151 acquires individualposition related information from each of the one or more dynamic APs200 via the network communication unit 110, thereby acquiring the DAPposition related information.

For example, the target device is the base station 10 or the terminaldevice 20. When the target device is the terminal device 20, theinformation acquiring section 151 acquires target device positionrelated information from the terminal device 20 via the networkcommunication unit 110. Meanwhile, when the target device is the basestation 10, the information acquiring section 151, for example, acquirestarget device position related information stored in the storage unit120 (i.e. information relating to the position of the base station 10).

For example, the plurality of access points include one or more relaystations especially in the third embodiment. The information acquiringsection 151 further acquires fourth position related information (“relaystation position related information” below) relating to the positionsof the one or more relay stations.

For example, the information acquiring section 151 acquires relaystation position related information (i.e. information relating to theposition of the relay station 400) stored in the storage unit 120.

DAP Position Related Information

For example, the DAP position related information includes informationrelating to a change in the position of each of the one or more dynamicAPs 200. This point has been described in the first embodiment.

Additionally, the one or more dynamic APs 200 may be, for example, theone dynamic AP 200 or the plurality of dynamic APs 200 in the thirdembodiment.

Target Device Position Related Information

The content of target device position related information has beendescribed in the first embodiment.

Relay Station Position Related Information

The relay station position related information includes positionalinformation indicating the positions of the one or more relay stations400. For example, the positional information indicates a fixed positionthat does not change with the lapse of time. In addition, the positionalinformation is stored, for example, in the storage unit 120.

(Joint Transmission Determining Section 153)

The joint transmission determining section 153 determines whether or nota plurality of access points perform transmission of signals to a targetdevice in parallel using the same frequency resource.

For example, once the terminal device 20 requests communication in thecell 11 via a plurality of access points, the joint transmissiondetermining section 153 determines whether or not the plurality ofaccess points perform transmission of signals to a target device inparallel using the same frequency resource.

For example, the joint transmission determining section 153 determineswhether or not the one or more dynamic APs 200 and the one or more relaystations 400 perform transmission of signals to the terminal device 20in parallel using the same frequency resource in the third embodiment.In other words, the joint transmission determining section 143determines whether or not joint transmission to the terminal device 20in the downlink is performed.

More specifically, the joint transmission determining section 153, forexample, estimates the reception power of signals in the terminal device20, and compares the estimated reception power with a threshold, thesignals being transmitted by the base station 10. If the estimatedreception power falls below the threshold, the joint transmissiondetermining section 153 determines that the one or more dynamic APs 200and the one or more relay stations 400 perform transmission of signalsto the terminal device 20 in parallel using the same frequency resource.That is to say, it is determined that the macrocell base station 10transmits signals including the same data to the one or more dynamic APs200 and the one or more relay stations 400, and the one or more dynamicAPs 200 and the one or more relay stations 400 transmit the signalsincluding the same data to the terminal device 20 in parallel using thesame frequency resource.

For example, the joint transmission determining section 153 determineswhether or not the one or more dynamic APs 200 and the one or more relaystations 400 perform transmission of signals to the base station 10 inparallel using the same frequency resource in the third embodiment. Inother words, the joint transmission determining section 153 determineswhether or not joint transmission to the base station 10 in the uplinkis performed.

More specifically, the joint transmission determining section 153, forexample, estimates the reception power of signals in the base station10, and compares the estimated reception power with a threshold, thesignals being transmitted by the terminal device 20. If the estimatedreception power falls below the threshold, the joint transmissiondetermining section 153 determines that the plurality of dynamic APs 200perform transmission of signals to the base station 10 in parallel usingthe same frequency resource. That is to say, it is determined that theterminal device 20 transmits signals including the same data to the oneor more dynamic APs 200 and the one or more relay stations 400, and theone or more dynamic APs 200 and the one or more relay stations 400transmit the signals including the same data to the base station 10 inparallel using the same frequency resource.

(Scheduling Section 155)

The scheduling section 155 allocates a radio resource for performingtransmission of signals to the target device in parallel using the samefrequency resource. In other words, the scheduling section 155 allocatesa radio resource for performing joint transmission to the target device.

For example, when the communication system 1-3 is compliant with LTE,the radio resource is one or more resource blocks as an example. That isto say, the scheduling section 155 allocates one or more resource blocksfor performing joint transmission to each of a plurality of accesspoints.

The plurality of access points include, for example, the one or moredynamic APs 200 and the one or more relay stations 400 especially in thethird embodiment. Accordingly, the scheduling section 155 allocates eachof the one or more resource blocks to the one or more dynamic APs 200and the one or more relay stations 400.

In addition, the scheduling section 155, for example, generatesallocation information relating to the allocation of a radio resourcefor performing the transmission (i.e. transmission of signals to atarget device in parallel using the same frequency resource). This pointhas been described in the first embodiment.

The scheduling section 155 then provides, for example, the allocationinformation to the macrocell base station 10 via the networkcommunication unit 110. As a result, the allocation information istransmitted to the one or more dynamic APs 200 and the one or more relaystations 400, for example, by the macrocell base station 10. As aresult, the radio resource is used by each of the one or more dynamicAPs 200 and the one or more relay stations 400 for joint transmission inthe macrocell 11.

In addition, the scheduling section 155 provides the allocationinformation to the distance estimating section 157.

(Distance Estimating Section 157)

The distance estimating section 157 estimates the distance between thetarget device and each of the one or more dynamic APs 200 during thetransmission of signals to the target device on the basis of the DAPposition related information and the target device position relatedinformation. This point has been described in the first embodiment.

For example, when the target device is the terminal device 20, thedistance estimating section 157 estimates the distance between theterminal device 20 and each of the one or more relay stations 400 induring the transmission of signals to the terminal device 20 on thebasis of the relay station position related information and the targetdevice position related information in the third embodiment.Additionally, the distance between the terminal device 20 and each ofthe one or more relay stations 400 may also be estimated in the sametechnique for the distance between the terminal device 20 and the one ormore dynamic APs 200.

In addition, for example, information relating to the distance betweenthe base station 10 and each of the one or more relay stations 400 isprepared in advance, and stored in the storage unit 120 in the thirdembodiment. When the target device is the base station 10, theinformation relating to the distance is then acquired from the storageunit 120.

For example, the information relating to the distance between the basestation 10 and each of the one or more relay stations 400 includesinformation on the distance.

Additionally, the information relating to the distance between the basestation 10 and each of the one or more relay stations 400 may includeinformation on a propagation delay time between the base station 10 andthe one or more relay stations 400 instead of the information on thedistance or in combination with the information on the distance. Theinformation on a propagation delay time may be, for example, updated asrequired on the basis of a result obtained by actually measuring apropagation delay time.

(Transmission Timing Deciding Section 159)

The transmission timing deciding section 159 decides transmission timingof each of the plurality of access points for the transmission ofsignals to the target device on the basis of information relating to thedistance between the target device and each of the plurality of accesspoints. The information relating to the distance includes information onthe estimated distance between the target device and each of the one ormore dynamic APs 200.

In addition, for example, when the target device is the terminal device20, the information relating to the distance includes information on theestimated distance between the terminal device 20 and each of the one ormore relay stations 400 in the third embodiment. Meanwhile, for example,when the target device is the base station 10, the information relatingto the distance includes the information relating to the distancebetween the base station 10 and each of the one or more relay stations400.

For example, the decided transmission timing is timing of thetransmission in a transmission frame in which the transmission ofsignals to the terminal device 20 is performed.

As specific processing, the transmission timing deciding section 159,for example, selects the farthest device from the target device amongthe one or more dynamic APs 200 and the one or more relay stations 400.The device is selected on the basis of information on the estimateddistance between the terminal device 20 and each of the one or moredynamic APs 200 and information relating to the distance between thetarget device and each of the one or more relay stations 400. Theinformation relating to the distance between the target device and eachof the one or more relay stations 400 is information on the estimateddistance between the terminal device 20 and each of the one or morerelay stations 400 if the target device is the terminal device 20. Forexample, the information relating to the distance between the targetdevice and each of the one or more relay stations 400 is information(prepared in advance) on the distance between the terminal device 20 andeach of the one or more relay stations 400 if the target device is thebase station 10. The transmission timing deciding section 159 thendecides, as transmission timing of the selected device (dynamic AP 200or relay station 400), a starting point of a transmission frame withwhich the transmission (i.e. joint transmission) of signals to thetarget device is performed, for example.

The transmission timing deciding section 159, for example, estimates apropagation delay time (which will be referred to as “referencepropagation delay time” below) from the selected device to the targetdevice on the basis of the information on the distance between thetarget device and the selected device. In addition, the transmissiontiming deciding section 159 estimates a propagation delay time ofsignals from the other individual devices of the one or more dynamic APs200 and the one or more relay stations 400 to the terminal device 20 forthe other individual devices on the basis of information on the distancebetween the terminal device 20 and the individual devices. Thetransmission timing deciding section 159 then calculates a differencebetween the estimated propagation delay time and the referencepropagation delay time. The transmission timing deciding section 159decides, as transmission timing of the individual devices (dynamic APs200 or relay stations 400), a time point that is delayed from thestarting time point of a transmission frame as much as the difference.

In this way, the transmission timing deciding section 159, for example,decides transmission timing of each of the one or more dynamic APs 200and the one or more relay stations 400 for the transmission (i.e. jointtransmission) of signals to the target device.

Additionally, when the information relating to the distance between thebase station 10 and each of the one or more relay stations 400 includesinformation on a propagation delay time between the base station 10 andthe one or more relay stations 400, the propagation delay time does nothave to be estimated.

The transmission timing deciding section 149 provides information on thedecided transmission timing to a plurality of access points via thenetwork communication unit 110, the plurality of access pointsperforming the transmission (i.e. joint transmission) of signals to thetarget device. The information on the decided transmission timing isprovided to the one or more dynamic APs 200 and the one or more relaystations 400 in the third embodiment.

Additionally, the transmission timing deciding section 159 may decidethe transmission timing further on the basis of propagation pathinformation relating to a propagation path between the target device andeach of the one or more dynamic APs 200. This point has been describedin the first embodiment.

<3.2.2. Configuration of Relay Station>

An example of the configuration of the relay station 400 according tothe third embodiment will be described with reference to FIG. 18. FIG.18 is a block diagram illustrating an example of the configuration ofthe relay station 400 according to the third embodiment. FIG. 18illustrates that the relay station 400 includes a wireless communicationunit 410, a storage unit 420, and a control unit 430.

(Wireless Communication Unit 410)

The wireless communication unit 410 wirelessly communicates with anotherdevice. That is to say, the wireless communication unit 410 transmits asignal to the other device, and receives a signal transmitted by theother device.

For example, the wireless communication unit 410 wirelessly communicateswith the base station 10. For example, the wireless communication unit410 wirelessly communicates with the terminal device 20. In addition,the wireless communication unit 410 wirelessly communicates, forexample, with the dynamic AP 200.

The wireless communication unit 410 includes, for example, acommunication antenna, an RF circuit, and another communicationprocessing circuit.

(Storage Unit 420)

The storage unit 420 stores a program and data for operating the relaystation 400. The storage unit 420 includes, for example, a magneticstorage device such as a hard disk, or nonvolatile memory such as EEPROMand flash memory.

(Control Unit 430)

The control unit 430 provides a variety of functions of the relaystation 400. The control unit 430 includes, for example, a processorsuch as a CPU or a DSP. The control unit 430 then provides the varietyof functions by executing a program stored in the storage unit 420 oranother storage medium.

The control unit 430 includes a transmission timing acquiring section431 and a communication control section 433.

(Transmission Timing Acquiring Section 431)

The transmission timing acquiring section 431 then acquires informationon the transmission timing of the relay station 400 for the transmission(i.e. joint transmission) of signals to the terminal device 20.

In addition, the transmission timing acquiring section 431 acquiresallocation information including information on a transmission framewith which the transmission of signals to the terminal device 20 isperformed.

For example, once the control server 100-3 provides the allocationinformation and the information on the transmission timing to the basestation 10, the base station 10 transmits the allocation information andthe information on the transmission timing to the relay station 400. Thetransmission timing acquiring section 431 then acquires the allocationinformation and the information on the transmission timing via thewireless communication unit 410.

(Communication Control Section 433)

The communication control section 433 controls communication performedby the relay station 400.

In particular, based on the transmission timing of the relay station 400for the transmission (i.e. joint transmission) of signals to a targetdevice in parallel using the same frequency resource, the communicationcontrol section 433 controls the transmission of the relay station 400for the transmission.

For example, once the transmission timing acquiring section 431 acquirestransmission timing and allocation information, the communicationcontrol section 433 causes the wireless communication unit 410 totransmit signals to the target device at the transmission timing in atransmission frame in which the transmission of signals to the targetdevice is performed.

<<3.3. Flow of Processing>>

Next, an example of communication control processing according to thethird embodiment will be described with reference to FIGS. 19A to 20.

(Communication Control Processing for Downlink)

First of all, an example of communication control processing for thedownlink will be described with reference to FIGS. 19A to 19C. Each ofFIGS. 19A to 19C is a flowchart illustrating an example of a schematicflow of communication control processing according to the thirdembodiment for the downlink.

First of all, the information acquiring section 241 of the dynamic AP200 acquires individual position related information relating to theposition of the dynamic AP 200 (step S801). Furthermore, the terminaldevice 20 also acquires position related information relating to theposition of the terminal device 20 (step S803).

The terminal device 20 then transmits a request for communication by theterminal device 20 in the cell 11 and the position related informationrelating to the position of the terminal device 20 to the dynamic AP 200and the relay station 400 (steps S805 and S807).

The information providing section 243 of the dynamic AP 200 transmitsthe request for communication by the terminal device 20 in the cell 11,the position related information relating to the position of theterminal device 20, and the individual position related informationrelating to the position of the dynamic AP 200 to the base station 10via the wireless communication unit 210 (S809).

In addition, the relay station 400 transmits a request for communicationby the terminal device 20 in the cell 11 and the position relatedinformation relating to the position of the terminal device 20 to thebase station 10 via the wireless communication unit 410 (S811).

Thereafter, the base station 10 transmits the request for communicationby the terminal device 20 in the cell 11, the position relatedinformation relating to the position of the terminal device 20, and theindividual position related information relating to the position of thedynamic AP 200 to the control server 100-3 (S813).

The joint transmission determining section 153 of the control server100-3 then determines whether or not the dynamic AP 200 and the relaystation 400 perform transmission of signals to the terminal device 20 inparallel using the same frequency resource (S815). Here, for example,the joint transmission determining section 153 determines that thetransmission of signals to the terminal device 20 is performed.

The scheduling section 155 of the control server 100-3 then allocates aradio resource for performing the transmission of signals to theterminal device 20 (S817).

Moreover, the distance estimating section 157 of the control server100-3 estimates the distance between the terminal device 20 and each ofthe dynamic AP 200 and the relay station 400 during the transmission ofsignals to the terminal device 20 on the basis of the position relatedinformation on each device (S819).

The transmission timing deciding section 159 of the control server 100-3then decides transmission timing of each of the dynamic AP 200 and therelay station 400 for the transmission (i.e. joint transmission) ofsignals to the terminal device 20 on the basis of information on theestimated distance (S821).

Thereafter, the control server 100-3 transmits downlink data addressedto the terminal device 20, allocation information relating to theallocation of a radio resource, and information on the decidedtransmission timing to the base station 10 (S823).

Moreover, the base station 10 transmits the downlink data addressed tothe terminal device 20, the allocation information, and the informationon the decided transmission timing to the dynamic AP 200 and the relaystation 400 (S825 and S827).

Thereafter, the dynamic AP 200 and the relay station 400 wait for atarget frame corresponding to the allocated radio resource (S829 andS831).

The communication control section 433 of the relay station 400 thentransmits signals including the downlink data to the terminal device 20with the target frame at the decided transmission timing of the relaystation 400 (S833).

The communication control section 247 of the dynamic AP 200 alsotransmits signals including the downlink data to the terminal device 20with the target frame at the decided transmission timing of the dynamicAP 200 (S835).

(Communication Control Processing for Uplink)

Furthermore, an example of communication control processing for theuplink will be described with reference to FIGS. 20A to 20C. Each ofFIGS. 20A to 20C is a flowchart illustrating an example of a schematicflow of communication control processing according to the thirdembodiment for the downlink.

First of all, the information acquiring section 241 of the dynamic AP200 acquires individual position related information relating to theposition of the dynamic AP 200 (step S901).

The terminal device 20 then transmits a request for communication by theterminal device 20 in the cell 11 to the dynamic AP 200 and the relaystation 400 (steps S903 and S905).

The information providing section 243 of the dynamic AP 200 transmitsthe request for communication by the terminal device 20 in the cell 11and the individual position related information relating to the positionof the dynamic AP 200 to the base station 10 via the wirelesscommunication unit 210 (S907).

In addition, the relay station 400 transmits a request for communicationby the terminal device 20 in the cell 11 to the base station 10 via thewireless communication unit 410 (S909).

Thereafter, the base station 10 transmits the request for communicationby the terminal device 20 in the cell 11 and the individual positionrelated information relating to the position of the dynamic AP 200 tothe control server 100-3 (S911).

The joint transmission determining section 153 of the control server100-3 then determines whether or not the dynamic AP 200 and the relaystation 400 perform transmission of signals to the base station 10 inparallel using the same frequency resource (S913). Here, for example,the joint transmission determining section 153 determines that thetransmission of signals to the base station 10 is performed.

The scheduling section 155 of the control server 100-3 then allocates aradio resource for performing the transmission of signals to the basestation 10 (S915).

Moreover, the distance estimating section 157 of the control server100-3 estimates the distance between the base station 10 and the dynamicAP 200 during the transmission of signals to the base station 10 on thebasis of the position related information on each device (S917).

The transmission timing deciding section 159 of the control server 100-3then decides transmission timing of each of the dynamic AP 200 and therelay station 400 for the transmission (i.e. joint transmission) ofsignals to the base station 10 on the basis of information on theestimated distance and information relating to the distance between thebase station 10 and the relay station 400 (S919).

Thereafter, the control server 100-3 transmits allocation informationrelating to the allocation of a radio resource and information on thedecided transmission timing to the base station 10 (S921).

Moreover, the base station 10 transmits the allocation information andthe information on the decided transmission timing to the relay station400 and the dynamic AP 200 (S923 and S925).

Thereafter, the terminal device 20 transmits signals including uplinkdata to the dynamic AP 200 and the relay station 400 (S927 and S929).

The dynamic AP 200 and the relay station 400 then wait for a targetframe corresponding to the allocated radio resource (S931 and S933).

Thereafter, the communication control section 433 of the relay station400 transmits signals including the uplink data to the base station 10with the target frame at the decided transmission timing of the relaystation 400 (S935).

The communication control section 247 of the dynamic AP 200 alsotransmits signals including the uplink data to the base station 10 withthe target frame at the decided transmission timing of the dynamic AP200 (S937).

<<3.4. Modified Example>>

Next, a modified example of the third embodiment will be described withreference to FIGS. 21 and 22.

FIG. 16 has illustrated an example in which the one or more dynamic APs200 and the one or more relay stations 400 communicate with the basestation 10 of the cell 11, and perform joint transmission to the basestation 10 or the terminal device 20 as an example of the thirdembodiment.

(First Modified Example)

Meanwhile, the one or more dynamic APs 200 and the one or more relaystations 400 may also communicate with a small cell base station 30 of asmall cell 31 a part or the whole of which overlaps with the cell 11,and perform joint transmission to the small cell base station 30 or theterminal device 20 as a first modified example of the third embodiment.That is to say, a target device that is a target of joint transmissionmay be a small cell base station. A specific example of the firstmodified example will be described with reference to FIG. 21.

FIG. 21 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system 1-3A according to the firstmodified example of the third embodiment. As illustrated in FIG. 21, thecommunication system 1-3A may include the small cell base station 30 inthe first modified example of the third embodiment. When the dynamic AP200 and the relay station 400 communicate with the small cell basestation 30, transmission of signals to the small cell base station 30 orthe terminal device 20 in parallel may be performed using the samefrequency resource. As with the base station 10, transmission timing ofjoint transmission to the terminal device 20 or the small cell basestation 30 is decided even in such a case of the small cell base station30.

(Second Modified Example)

A part of the one or more dynamic APs 200 and the one or more relaystations 400 may communicate with the small cell base station 30 of thesmall cell 31, and the rest of the one or more dynamic APs 200 and theone or more relay stations 400 may communicate with the base station 10as a second modified example of the third embodiment. The one or moredynamic APs 200 and the one or more relay stations 400 may then performjoint transmission to the terminal device 20 in this case. A specificexample of the second modified example will be described with referenceto FIG. 22.

FIG. 22 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system 1-3B according to the secondmodified example of the third embodiment. As illustrated in FIG. 22, thecommunication system 1-3B may also include the small cell base station30 in the first modified example of the third embodiment. When the relaystation 400 communicates with the base station 10 and the dynamic AP 200communicates with the small cell base station 30, the dynamic AP 200 andthe relay station 400 may perform transmission of signals to theterminal device 20 in parallel using the same frequency resource.Transmission timing for joint transmission to the terminal device 20 isdecided in the same way even in such a case.

It goes without saying that if both of the one or more dynamic APs 200and the one or more relay stations 400 have any chance to communicatewith the base station 10 (i.e. macro cell base station), the one or moredynamic APs 200 and the one or more relay stations 400 may performtransmission of signals to the base station 10 or the terminal device 20in parallel using the same frequency resource in the second modifiedexample. If both of the one or more dynamic APs 200 and the one or morerelay stations 400 have any chance to communicate with the small cellbase station 30, the one or more dynamic APs 200 and the one or morerelay stations 400 may perform transmission of signals to the terminaldevice 20 or the small cell base station 30 in parallel using the samefrequency resource.

<<<4. Conclusion>>>

FIGS. 1 to 22 have been used so far to describe each of the devices andprocessing according to each embodiment of the present disclosure.According to an embodiment of the present disclosure, DAP positionrelated information and target device position related information areacquired, the DAP position related information relating to the positionsof the one or more dynamic APs 200 among a plurality of access pointsthat perform transmission of signals to a target device in parallelusing the same frequency resource, the target device position relatedinformation relating to the position of the target device. In addition,the distance between the target device and each of the one or moredynamic APs 200 during the transmission is estimated on the basis of theDAP position related information and the target device position relatedinformation. Furthermore, transmission timing of each of the pluralityof access points for the transmission is decided on the basis ofinformation relating to the distance between the target device and eachof the plurality of access points, the information including informationon the estimated distance. Moreover, the DAP position relatedinformation includes information relating to a change in the position ofeach of the one or more dynamic APs 200.

Accordingly, it becomes possible to increase the reception power levelof signals with joint transmission even when one or more of a pluralityof access points may move, the plurality of access points performingtransmission (i.e. joint transmission) of the signals to a target devicein parallel using the same frequency resource. That is to say, even ifthe dynamic AP 200 moves before performing joint transmission, it ispossible to reduce a gap of the timing at which a target device receivessignals of the joint transmission because the transmission timing isdecided on the basis of the distance between the target device and themoved dynamic AP 200. As a result, the reception power level of thesignals in the target device is increased.

In addition, the use of the movable dynamic AP 200 as an access pointmakes it possible to form a flexible network. That is to say, it ispossible to increase the reception power of signals by use of jointtransmission while forming a flexible network.

An increase in the reception power of signals may result in increasedtransmission speed for a target device and increased network capacity.

Regarding Downlink

For example, the target device is the terminal device 20.

Accordingly, it becomes possible to increase the reception power levelof signals in the terminal device 20 for joint transmission in thedownlink.

Furthermore, target device position related information includes, forexample, information relating to a change in the position of theterminal device 20.

Accordingly, it becomes possible to increase the reception power levelof the signals with joint transmission even if the terminal device 20,which is a target of the joint transmission, may move. That is to say,even if the terminal device 20 moves before performing jointtransmission, it is possible for the terminal device 20 to receivesignals of the joint transmission at the same timing becausetransmission timing is decided on the basis of the distance between themoved terminal device 20 and the moved dynamic AP 200. As a result, thereception power level of the signals in the terminal device 20 isincreased.

Additionally, the plurality of access points include, for example, oneor more base stations as described in the second embodiment.

Accordingly, it becomes possible to increase the reception power levelof signals in the terminal device 20 with joint transmission even whenthere is only a single dynamic AP positioned around the terminal device20. It also becomes possible to perform joint transmission to theterminal device 20 with a smaller number of the dynamic APs 200 fromanother perspective. That is to say, it is possible to reduce the powerconsumption of the dynamic AP 200.

For example, the one or more base stations include at least one smallcell base station 300.

Accordingly, the small cell base station 300 positioned around theterminal device 20 can increase the reception power level of signals inthe terminal device 20 with joint transmission even when the only onedynamic AP 200 is positioned around the terminal device 20. To thecontrary, the dynamic AP 300 positioned around the terminal device 20can increase the reception power level of signals in the terminal device20 with joint transmission even when the only one small cell basestation 300 is positioned around the terminal device 20.

It also becomes possible to perform joint transmission to the terminaldevice 20 with a smaller number of the dynamic APs 200 from anotherperspective, when the small cell base station 300 is installed. That isto say, it is possible to reduce the power consumption of the dynamic AP200.

Meanwhile, the one or more base stations may include at least the onemacrocell base station 10 as described in the modified example of thesecond embodiment.

Accordingly, it becomes possible for a single dynamic AP alone, which ispositioned around the terminal device 20, to increase the receptionpower level of signals in the terminal device 20 when the small cellbase station 300 is not installed or when the small cell base station300 is not positioned around the terminal device 20.

Regarding Uplink

For example, the target device is a base station.

Accordingly, it becomes possible to increase the reception power levelof signals in a base station for joint transmission in the uplink.

Furthermore, the target device may be the mall cell base station 30 asdescribed in the first modified example of the first embodiment and thefirst modified example of the third embodiment.

Accordingly, it becomes possible to increase the reception power levelof signals in the small cell base station 30.

Regarding Downlink and Uplink

A plurality of access points are, for example, the dynamic APs 200 asdescribed in the modified examples of the first embodiment.

Accordingly, it is possible to increase the reception power level ofsignals in a target device (terminal device 20 or base station) onlywith the dynamic AP 200 positioned within the cell. It is thus possibleto perform effective joint transmission while forming a more flexiblenetwork.

Additionally, a plurality of access points include, for example, the oneor more relay stations 400, which provide relays to the target device,as described in the modified examples of the third embodiment.

Accordingly, the relay station 400 positioned around the terminal device20 can increase the reception power level of signals in the terminaldevice 20 with joint transmission even when the one dynamic AP 200 aloneis positioned around the terminal device 20. To the contrary, thedynamic AP 200 positioned around the terminal device 20 can increase thereception power level of signals in the terminal device 20 with jointtransmission even when the one relay station 400 alone is positionedaround the terminal device 20.

It also becomes possible to perform joint transmission to the terminaldevice 20 with a smaller number of the dynamic APs 200 from anotherperspective, when the relay station 400 is installed. That is to say, itis possible to reduce the power consumption of the dynamic AP 200.

Others

Additionally, the transmission timing may be decided further on thebasis of propagation path information relating to a propagation pathbetween the target device and each of the one or more dynamic APs 200.

Accordingly, a propagation delay time according to the characteristicsof a propagation path may be calculated, so that more approximatetransmission timing can be decided. As a result, it is possible tofurther reduce a gap of the timing at which a target device receivessignals of joint transmission. As a result, the reception power level ofthe signals in the target device is further increased.

In addition, the distance between the target device and each of the oneor more dynamic APs 200 during the transmission is, for example,estimated further on the basis of allocation information relating to theallocation of a radio resource for performing the transmission.

The allocation information includes, for example, information on atransmission frame with which the transmission is performed. The decidedtransmission timing is timing of the transmission in the transmissionframe.

Accordingly, it becomes possible to estimate the position of the moveddynamic AP 200 during the joint transmission, even when a radio resource(such as a transmission frame) for joint transmission is flexiblydecided.

The preferred embodiments of the present disclosure have been describedabove with reference to the accompanying drawings, whilst the presentdisclosure is not limited to the above examples, of course. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

For example, an example has been described in which information relatingto a change in the position of a dynamic AP includes positionalinformation and movement information on the dynamic AP, but the presentdisclosure is not limited to the example. The information relating to achange in the position may be another kind of information that allows achange in the position of a dynamic AP to be estimated. As an example,the information relating to a change in the position may be positionalinformation on a dynamic AP at a plurality of time points. According tosuch a kind of information, for example, it becomes possible to acquireinformation equal to the movement information.

Meanwhile, an example has been described in which the distance between atarget device and a dynamic AP is estimated on the basis of allocationinformation relating to the allocation of a radio resource, but thepresent disclosure is not limited to the example. For example, if aradio resource (such as a transmission frame) with which jointtransmission is performed has been decided in advance, the allocationinformation does not have to be used to estimate the distance.

The transmission timing may be decided in terms of the Doppler Effect inthe movement of a dynamic AP (and a terminal device).

An example has been described in which the transmission timing isdecided on the basis of propagation path information, but the presentdisclosure is not limited to the example. For example, the propagationpath information does not have to be used to decide the transmissiontiming. Apart from the decision of the transmission timing, a change ina phase (i.e. phase shift) of a propagation path may be overcome by theprocessing of a dynamic AP.

An example has been described in which a communication system includes acontrol server, but the present disclosure is not limited to theexample. For example, a base station may have the function of thecontrol server.

An example has been described in which a terminal device and a dynamicAP are smartphones, but the present disclosure is not limited to theexample. For example, these devices may be other devices such as tabletterminals, personal computers (PCs), personal digital assistants,electronic book terminals, car navigation systems, and game consoles.

Processing steps in the communication control processing in the presentdescription do not necessarily have to be performed in the chronologicalorder described in the flowcharts. For example, the processing steps inthe communication control processing may be performed in order differentfrom the order described as the flowcharts, or may be performed inparallel.

It is also possible to create a computer program for causing hardwaresuch as a CPU, ROM, and RAM built in a communication control device(such as a control server) and a wireless communication device (such asa dynamic AP) to execute the communication control processing and thesame function as that of each configuration of the wirelesscommunication control device. There is also provided a storage mediumhaving the computer program stored therein.

Additionally, the present disclosure may also be configured as below.

(1)

A communication control device including:

an acquiring section configured to acquire first position relatedinformation and second position related information, the first positionrelated information relating to positions of one or more wirelesscommunication devices among a plurality of access points that performtransmission of signals to a target device in parallel using anidentical frequency resource, the second position related informationrelating to a position of the target device;

an estimating section configured to estimate a distance between thetarget device and each of the one or more wireless communication devicesduring the transmission on the basis of the first position relatedinformation and the second position related information; and

a deciding section configured to decide transmission timing of each ofthe plurality of access points for the transmission on the basis ofinformation that includes information on the estimated distance andrelates to a distance between the target device and each of theplurality of access points,

wherein the first position related information includes informationrelating to a change in the position of each of the one or more wirelesscommunication devices.

(2)

The communication control device according to (1),

wherein the target device is a terminal device.

(3)

The communication control device according to (2),

wherein the second position related information includes informationrelating to a change in the position of the target device.

(4)

The communication control device according to (2) or (3),

wherein the plurality of access points include one or more basestations.

(5)

The communication control device according to (4),

wherein the acquiring section further acquires third position relatedinformation relating to positions of the one or more base stations,

wherein the estimating section estimates a distance between the targetdevice and each of the one or more base stations during the transmissionon the basis of the second position related information and the thirdposition related information,

wherein the information relating to the distance between the targetdevice and each of the plurality of access points includes informationon the estimated distance between the target device and each of the oneor more base stations, and

wherein the third position related information further includespositional information indicating the positions of the one or more basestations.

(6)

The communication control device according to (4) or (5),

wherein the one or more base stations include at least one base stationof a small cell.

(7)

The communication control device according to any one of (4) to (6),

wherein the one or more base stations include at least one base stationof a macrocell.

(8)

The communication control device according to (1),

wherein the target device is a base station.

(9)

The communication control device according to (8),

wherein the second position related information includes positionalinformation indicating the position of the target device.

(10)

The communication control device according to (8) or (9),

wherein the target device is a base station of a small cell.

(11)

The communication control device according to (1),

wherein a plurality of access points are the one or more wirelesscommunication devices.

(12)

The communication control device according to (1),

wherein the plurality of access points include one or more relaystations that provide relays to the target device.

(13)

The communication control device according to (12),

wherein the target device is a base station, and

wherein the information relating to the distance between the targetdevice and each of the plurality of access points includes informationon a distance between the target device and the one or more relaystations or information on a propagation delay time between the targetdevice and the one or more relay stations.

(14)

The communication control device according to any one of (1) to (13),

wherein the deciding section decides the transmission timing further onthe basis of propagation path information relating to a propagation pathbetween the target device and each of the one or more wirelesscommunication devices.

(15)

The communication control device according to (14),

wherein the propagation path information includes information relatingto a change in a phase of the propagation path.

(16)

The communication control device according to any one of (1) to (15),

wherein the estimating section estimates the distance further on thebasis of allocation information relating to an allocation of a radioresource for performing the transmission.

(17)

The communication control device according to (16),

wherein the allocation information includes information on atransmission frame with which the transmission is performed, and

wherein the decided transmission timing is timing of transmission in thetransmission frame.

(18)

A communication control method including:

acquiring first position related information and second position relatedinformation, the first position related information relating topositions of one or more wireless communication devices among aplurality of access points that perform transmission of signals to atarget device in parallel using an identical frequency resource, thesecond position related information relating to a position of the targetdevice;

estimating a distance between the target device and each of the one ormore wireless communication devices during the transmission on the basisof the first position related information and the second positionrelated information; and

deciding transmission timing of each of the plurality of access pointsfor the transmission on the basis of information that includesinformation on the estimated distance and relates to a distance betweenthe target device and each of the plurality of access points,

wherein the first position related information includes informationrelating to a change in the position of each of the one or more wirelesscommunication devices.

(19)

A wireless communication device including:

a communication control section configured to operate the wirelesscommunication device as an access point; and

an acquiring section configured to, when the wireless communicationdevice and one or more access points perform transmission of signals toa target device in parallel using an identical frequency resource,acquire information on transmission timing of the wireless communicationdevice for the transmission after a communication control device decidestransmission timing of the wireless communication device and each of theone or more access points for the transmission,

wherein the communication control section controls transmission of thewireless communication device for the transmission on the basis of thetransmission timing of the wireless communication device for thetransmission,

wherein the transmission timing of the wireless communication device andeach of the one or more access points for the transmission is decided onthe basis of information relating to a distance between the targetdevice and the wireless communication device and between the targetdevice and each of the one or more access points,

wherein the information relating to the distance includes information ona distance to be estimated between the target device and the wirelesscommunication device during the transmission,

wherein the distance to be estimated is estimated on the basis ofindividual position related information relating to a position of thewireless communication device and position related information relatingto a position of the target device, and

wherein the individual position related information includes informationon a change in the position of the wireless communication device.

(20)

The communication device according to (19), further including:

an acquiring section configured to acquire the individual positionrelated information; and

a providing section configured to provide the individual positionrelated information to the communication control device.

REFERENCE SIGNS LIST

-   1 communication system-   10 base station (macrocell base station)-   11 cell (macrocell)-   20 terminal device-   30 small cell base station-   31 small cell-   100 control server-   131, 141, 151 information acquiring section-   137, 147, 157 distance estimating section-   139, 149, 159 transmission timing deciding section-   200 dynamic AP-   241 information acquiring section-   243 information providing section-   245 transmission timing acquiring section-   247 communication control section-   300 small cell base station-   400 relay station

The invention claimed is:
 1. A communication control device, comprising:circuitry configured to: acquire a first position related informationand a second position related information, the first position relatedinformation relating to position of at least one wireless communicationdevice among a plurality of access points, the second position relatedinformation relating to a position of a target device; generate anallocation information comprising identification information related toa frequency resource which is utilized for transmission of signal to atarget device, wherein the at least one wireless communication devicetransmits the signal to the target device in parallel based on thefrequency resource; estimate a distance between the target device andthe at least one wireless communication device during the transmissionbased on the first position related information and the second positionrelated information; and determine transmission timing of each of theplurality of access points for the transmission based on the estimateddistance and a distance between the target device and each of theplurality of access points, wherein the first position relatedinformation further includes information relating to a change in theposition of the at least one wireless communication device.
 2. Thecommunication control device according to claim 1, wherein the targetdevice is a terminal device.
 3. The communication control deviceaccording to claim 2, wherein the second position related informationfurther includes information relating to a change in the position of thetarget device.
 4. The communication control device according to claim 2,wherein the plurality of access points include at least one basestation.
 5. The communication control device according to claim 4,wherein the circuitry is further configured to acquire a third positionrelated information relating to position of the at least one basestation, estimate a distance between the target device and at least onebase station during the transmission based on the second positionrelated information and the third position related information, whereinthe information relating to the distance between the target device andeach of the plurality of access points includes information on theestimated distance between the target device and the at least one basestation, and wherein the third position related information furtherincludes positional information indicating the position of the at leastone base station.
 6. The communication control device according to claim4, wherein the at least one base station includes at least one basestation of a small cell.
 7. The communication control device accordingto claim 4, wherein the at least one base station includes at least onebase station of a macrocell.
 8. The communication control deviceaccording to claim 1, wherein the target device is a base station. 9.The communication control device according to claim 8, wherein thesecond position related information further includes positionalinformation indicating the position of the target device.
 10. Thecommunication control device according to claim 8, wherein the targetdevice is a base station of a small cell.
 11. The communication controldevice according to claim 1, wherein a plurality of access points arethe at least one wireless communication device.
 12. The communicationcontrol device according to claim 1, wherein the plurality of accesspoints include at least one relay station that provides relays to thetarget device.
 13. The communication control device according to claim12, wherein the target device is a base station, and wherein theinformation relating to the distance between the target device and eachof the plurality of access points includes information on a distancebetween the target device and the at least one relay station orinformation on a propagation delay time between the target device andthe at least one relay station.
 14. The communication control deviceaccording to claim 1, wherein the circuitry is further configured todetermine the transmission timing further based on propagation pathinformation relating to a propagation path between the target device andthe at least one wireless communication device.
 15. The communicationcontrol device according to claim 14, wherein the propagation pathinformation includes information relating to a change in a phase of thepropagation path.
 16. The communication control device according toclaim 1, wherein the circuitry is further configured to estimate thedistance further based on the allocation information relating to anallocation of a radio resource for the transmission.
 17. Thecommunication control device according to claim 16, wherein theallocation information includes information on a transmission frame withwhich the signal is transmitted, and wherein the determined transmissiontiming is timing of transmission in the transmission frame.
 18. Acommunication control method, comprising: acquiring a first positionrelated information and a second position related information, the firstposition related information relating to positions of at least onewireless communication device among a plurality of access points, thesecond position related information relating to a position of a targetdevice; generating an allocation information comprising identificationinformation related to a frequency resource which is utilized fortransmission of signal to a target device, wherein the at least onewireless communication device transmits the signal to the target devicein parallel based on the frequency resource; estimating a distancebetween the target device and the at least one wireless communicationdevice during the transmission, based on the first position relatedinformation and the second position related information; determiningtransmission timing of each of the plurality of access points for thetransmission based on the estimated distance and a distance between thetarget device and each of the plurality of access points, wherein thefirst position related information includes information relating to achange in the position of the at least one wireless communicationdevice.
 19. A wireless communication device, comprising: circuitryconfigured to: operate the wireless communication device as an accesspoint; receive an allocation information comprising identificationinformation related to a frequency resource which is utilized fortransmission of signals to a target device, wherein the wirelesscommunication device and at least one access point transmit the signalsto a target device in parallel based on the frequency resource; acquireinformation on transmission timing of the wireless communication devicefor the transmission based on a communication control device thatdetermines transmission timing of the wireless communication device andthe at least one access point for the transmission; control transmissionof the wireless communication device for the transmission based on thetransmission timing of the wireless communication device for thetransmission, wherein the transmission timing of the wirelesscommunication device and the at least one access point for thetransmission is determined based on information relating to a distancebetween the target device and the wireless communication device andbetween the target device and the at least one access point, wherein theinformation relating to the distance includes information on a distanceto be estimated between the target device and the wireless communicationdevice during the transmission, wherein the distance to be estimated isestimated based on individual position related information relating to aposition of the wireless communication device and position relatedinformation relating to a position of the target device, and wherein theindividual position related information includes information on a changein the position of the wireless communication device.
 20. The wirelesscommunication device according to claim 19, wherein the circuitry isfurther configured to: acquire the individual position relatedinformation; and provide the individual position related information tothe communication control device.